北海道東部における白亜系 - 第三系の境界について

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(1)Title. 北海道東部における白亜系 - 第三系の境界について. Author(s). 吉田, 三郎. Citation. 北海道学芸大学紀要. 第二部. B, 生物学,地学,農学編, 12(1): 14-38. Issue Date. 1961-08. URL. http://s-ir.sap.hokkyodai.ac.jp/dspace/handle/123456789/5740. Rights. Hokkaido University of Education.

(2) Vol. 12, No. 1 II B. Journal of Hokkaido Gakugei University. Aug., 1961. The Cretaceous-Tertiary Boundary m Eastern Hokkaido, Japan Saburo YOSHIDA Geological Institute, Kushiro Branch, Hokka ido Gakugei University. B3. ABSTRACT The Nemuro group, which is unconformably overlain by the Lower Tertiary Urahoro and Ombetsu groups, crops out in eastern Hokkaido. On the basis of stratigraphy and mega-and microfaunas, the problem of the boundary between Upper Cretaceous and Lower Tertiary is discussed. In conclusion, the geological age of the Nemuro group is determined as uppermost Cretaceous, and is proposed a new term "Nemuroan" for the sedimentational stage of the Nemuro group. Acknowledgments The present writer takes this opportunity of expressing his gratitude to Prof. Wataru HASHIMOTO, Geological and. Mineralogical Institute, Tokyo. University of Education, for valuable advice, for. permission to freely use his literature, for taking the trouble of proof-reading and for sincere encouragment throughout the course of this study. The present writer is also indebted to Prof. Yasuo SASA, Department of Geology and Mineralogy, Hokkaido University, for permission to use his literature, for valuable suggestions cncerning the field and discussion with regard to the stratigraphy of the Cretaceous and Tertiary deposits of eastern Hokkaido. During the course of the present work, the present writer received valuable support from the following persons to whom he takes this opportunity of expressing his deep gratitude. Prof. Kiyoshi ASANO, Institute of Geology and Paleontology, Tohoku University ; Prof. Tatsuro MATSUMOTO, Department of Geology, Kyushii University ;. Dr. Sutekazu NAGAO, Geological. Survey of Hokkaido ; Dr. Yokichi TAKAYANAGI, Institute of Geology and Paleontology. T ohoku University ; Mr. Takashi MATSUNAGA, Japan Petroleum Exploration Co., Ltd., Tokyo ; Messrs. Hisaichi IWAMOTO and Sei'ichi KOMURA. of the same company, Sapporo ; Mr. Masayuki AOKI, Yiibetsu Coal Mining Co., Ltd. ; Mr. Yutaka YOSHIMOTO, Nemuro High School ; Mr. Katsutoshi MITANI,. Geological Survey of Hokkaid<-, ; Dr. Saburo KANINO,. Geological and Mineralogical. Institute, Tokyo University of Education ; Messrs. Yoshio OKAZAKI and Hiroshi YOKOHIRA, Geological Institute, Kushiro Branch, Hokkaido Gakugei University.. -. 14-.

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(5) Saburo YOSHIDA Finally, the writer expresses his appreciation to the Japan Petroleum Exploration Company Ltd., the Ministry of Education, and the Hokkaido Development Agency for their financial support.. PREVIOUS. WORKS. As shown in Chart 1 and 2, the Nemuro group is the lowermost formation in the area of this report. It is unconformably overlain by the thick Tertiary sedimentary rocks. ChQrt I.. SUMMERY OF THE HISTORICAL ESTABLISHED. BY THE. REVIEW. PREVIOUS. I N DE X. OF. WORKERS. T~E. IN. GEOLOGICAL. SUCCESSIONS. THE KU SHIRO COAL. FIELD. MAP. 144". EASTERN. Harnbetsu. PACIFIC o,c. OCEAN. =~'~0=~2~0~~3~0= 4~- .r:..ol(rt.. Fig. 2. Index Map Showing the Position of Rivers, Valleys and Villages. Legend for the Names of Rivers, Valleys and Villages. Eastern Part of the Area 1. Hanasaki 2. Choboshi 3. Ochiishi 4. Esashito 5. Pomporoto 6. Hamanaka 7. Kiritappu 8. Mochirippu 9. Daikoku-iima 10. Monshizu 11. Oboro 12. Semposhi 13. Oshamappu 14. Atoega 15. Kombumori. Western Part of the Area B. K.. P.. Kawaruppu-zawa Kawakami-zawa Perutsunai-zawa. K. Jimbo (1890), who reported. c. M. R.. Nisho·zawa Tokomuro Rushin·zawa. E. 0.. s.. Jiniano -sawa Osappe·zawa Shunku-shitakara. Inoceramus from this group for the first time, -15-.

(6) The Cretaceous-Tertiary Boundary in Eastern Hokkaidii, Japan. concluded following the prevalent view of those days, that the Nemuro group 1s Tertiary in age and this fossil is a reworked one. G. Kobayashi (1914) reported in his paper on the geological study of the Urahoro coal field that the alternation of hard shale and sandstone of the Nemuro group belong to Lower Tertiary. K Watanabe (1915) suggested that the alternation of blackish hard shale and sandstone of this group is correlatable with Cretaceous. (?), but later he concluded (1917) that this. group belongs Cretaceous and is conformably overlain by the Lower Tertiary formations.. M. Kadokura (1918a, b) and Y.. Iizuka (1920) concluded that the relation. between the alternation of sandstone and shale of the Nemuro group and the conglomerate and sandstone of the. Urahoro group is conformable, and that all these. sedimentary rocks are Cretaceous in age. T. Suzuki (1923) reported Inoceramus from the alternation of sandstone and shale of the Nemuro group which crops out at Chanai, Hamanaka district, and also reported some undeterminable Ammonites from the shale of the same group exposed at Bin'nai, Semposhi.. He then correlated the above. alternation with Kadokura's alternation of sandstone and shale, and the shale with Kadokura's shale, thus concluding that these sedimentary rocks belong to. Upper. Cretaceous. Moreover, he concluded (1925, 193Gb) that the Nemuro group and the Paleogene formations are in fault contact. On the other hand, he (1930a) divided the Cretaceous formation into shale and conglomerate in ascending order, and stated that it is overlain unconformable (?) by Paleogene Tertiary sedimentary rocks. S. Tokuda (1929). considered that the conglomerate reported by T.. Suzuki. (1930a). is an. uppermost member of the Upper Cretaceous, and that Tertiary formations unconformably overlie this conglomerate. However, this conglomerate was first defined by H. Imai (1925) as the base of Tertiary deposits. Y. Sasa and S. Nishida (1935) and S. Nishida (1936) discovered many molluscan fossils from the Nemuro group exposed in the Urahoro coal field. They named the lowermost deposits in this area the "Nemuro Series'', and corresponded this series to the Hakobuchi Sandstone (" .Campanian-Maestrichtian) of the Ishikari coal field in central Hokkaidii. After all, the stratigraphical study of the Paleogene Urahoro group has been made by many students because this group is an important coal -bearing formation in the Kushiro coal field, but the Nemuro group has not yet been sufficiently studied stratigraphically and paleontologically. This neglect is due largely to the lack of interest on the part of the coal and petroleum industries in the Nemuro group which is poor in underground resources. After World War II, geological study of the Nemuro group in the report area became active.. The first important post-war study was made by Y. Sasa and L Hayashi. (1952) , in which they established the geological sequence of this group which croped out at Kombumori and the west coast of Akkeshi Bay.. The Nemuro group was. divided into five formations, namely, Monshizu, Sempiishi, Shiomi, Oshamappu and Chippomanai formations in ascending order. They also concluded that the thickness of the Nemuro group in this district amounts to more than lOOOm, and the group -. 16-.

(7) Sabur<• YOSHIDA. was unconformably overlain by the Paleogene Urahoro group, that according to the megafauna, the Nemuro group ranges from middle to upper part of Upper Cretaceous, that is, from. Urakawan (:...-Coniacian-Lower Campanian) to. Hetonai<J.n. (:..,Upper. Campanian-Maestrichtian) ; and that the Urahoro group which unconformably overlies the Nemuro group is Upper Eocene in age. T. Matsumoto (1953), in his detailed discussion on the whole Cretaceous system of Japan, stated that the Nemuro group and probable equivalent strata in the Kushiro coal field, the Hanasaki Peninsula and Shikotan of the south Kurile Islands probably correspond. to. Hetonaian or Upper Hetonaian. (._:Maestrichtian) . Since long before this, Y. Sasa (1932, 1934, 1940b, 1956b, 1957) has been publishing the result of his study on the geology of Shikotan, succeeded by many students as listed below who studied the Nemuro group in eastern Hokkaido. M. Kawai (1956a, b), S. Nagao (1957a, b, c), M. Tanai (1958), K. Mitani (1958) , S. Yoshida (1958), Y. Okazaki (1958), T. Yoshida (1958), K. Mitani, T. Fujiwara and K. Hasegawa (1958) , K. Mitani, W. Hashimoto and K Osanai (1959) , K. Hasegawa and K. Mitani (1959) , T. Fujiwara and K. Mitani (1959) , A. Mizuno and H. Hyakkoku (1960) . According to them, Upper Cretaceous.. the geological age of the. Nemuro group is considered to be. Contrary to the above view, S. Nishida and M. Minato (1950). suggested, on the basis of molluscan fossils, that the sedimentary rocks cropping out in the Island of Daikokujima correspond to the Poronai formation ("-;late Eocene-early Oligocene) of the Ishikari coal field and to the Shitakara formation. (:-~bte. Eocene-early. Oligocene) of the Kushiro coal field. On the other hand, Y. Sasa (1951, 1953) and S. Nagao (1957a, b) collected many fossils of molluscs and foraminifers in Daikokuiima belonging to the Nemuro group, and assigned the geological age of the group to Upper Cretaceous. In addition , A. Fukada ( 1953) and the present writer (1958c, 1960a) reported the discovery of some Ammonites from the Nemuro group.. On the basis of. these megafossils, Fukada concluded that the geological age of the Nemuro group ra.nged from Upper Urakawan (-;'"'Santonian-Lower Campanian) to Hetonaian, whereas the present writer defined it to be Upper Hetonaian.. As the result of the study of. foraminifers of the Nemuro group which crops out in the border of Kushiro and Tokachi Provinces, the present writer (1957a) concluded tentatively that this group may be assigned to. Upper Hetonaian.. He also suggested, on the ground of the. discovery of Globigerina, that this group is possibly Paleocene in age. Moreover, the present writer (1958d) studied the foraminifers from the Nemuro group which is exposed in the Hamanaka district, and concluded that the age of this group probably ranges from Maestrichtian to Danian.. Recently, K. Asano (1960) reported his discovery of. some species of planktonic foraminifera from the Nemuro group cropping out at Ochiishi of the Hanasaki Peninsula, and assigned this group to Danian age. As mentioned above, the geological age of the Nemuro group which is regarded as the basement of the report area has been assigned by most geologists to Upper Cretaceous, although ~. 17. ~.

(8) The Cretaceous-Tertiary Boundary in Eastern Hokkaidii, Japan. some students considered that this group belongs to later ages. The Boundary Between Upper Cretaceous and Lower Tertiary in Eastern Hokkaido, with Reference to the Geological Age of the Nemuro Group As was explained in the section on the previous works, the Urahoro group has been regarded as the lowermost member of the Tertiary system in eastern Hokkaidii, and the age of this group has been assigned by most geologists to the period ranging from late Eocene to early Oligocene, on the basis of fossils of molluscs, plants and microforaminifers. No evidence to indicate that the group is as old as Paleocene has been found. On the other hand, in the report area as far as investigated the Nemuro group is the oldest and constitute the basement. After the discovery of Inoceramus and Ammonites by T. Suzuki (1923) , the following megafossils were reported by Y. Sasa (1934, 1940 b) and T. Nagao and T. Matsumoto (1938-1939, 1940) from the Nemuro group and its probable equivalent strata cropping out in the Hanasaki Peninsula and Shikotan of the South Kurile Islands.. Inoceramus shikotanensis Nagao and Matsumoto I. kusiroensis Nagao and Matsumo!:o I. schmidti Michael. In addition, Pecten (Propeamussium ) cowperi yubarensis Yabe and Nagao, Margarita /uniculata Yokoyama and other molluscs were collected by S. Nishida (1936) from the Nemuro group which crops out in the Urahoro coal field. Due to the evidence of these megafossils, the Nemuro group has been considered to be assignable to Upper Cretaceous age. After World War II, preceded by the first important study by Y. Sasa and L Hayashi (1952) on the stratigraphy of the Nemuro group, many students have made geological and paleontological studies of this group, and assigned the geological age of the Nemuro group to the period ranging from the Upper Cretaceous Urakawan to Hetonaian. In the meantime, some students disagreed with the above-mentioned view.. Acila sp., Malletia poronaica (Yokoyama) , PeriPloma besshoensis (Yokoyama), Dentalium sp. and Voluta sp. from the sedimentary rocks cropping out in the Island of Daikokujima,. S. Nishida and M. Minato (1950) reported such molluscan fossils as. and considered that the geological age of these sedimentary rocks probably corresponds to the Poronai formation. ( ~.late. Eocene-early Oligocene) in the Ishikari coal field and. the Shitakara formation (."late Eocene-early Oligocene) in the Kushiro coal field. On the other hand, Y. Sasa (1951, 1953) and S. Nagao (1957a, b) reported many more fossils of molluscs and foraminifers from Daikokujima, and the fom1er concluded that the .geological age of the sedimentary rocks corresponds to the Hakobuchi group -. 18 :_.

(9) Saburil YOSHIDA ( ~ '· Santonian-Maestrichtian),. Hetonaian. and the latter to the range from Upper Urakawan to. (~··Santonian - Maestrichtian).. The fauna reported by them is as follows :. Nucula sp., Acila ( Truncacila) sp., Yoldia sp., Propeamussium sp., PeriPloma sp., Avellana problematica Nagao, Tessarolax japonica Yabe and Nagao, Pseudoperissitys bicarinata Nagao and Otatsume (after Y. Sasa) Acila sp., Propeamussium sp., Dentalium sp., Pleurotomaria sp., Coral and Brachiopods gen. et. sp. indet. Silicosigmoilina jutabaens1:s Asano, Haplaphragmoides sp., Dentalina cf. crinita Plummer, Nodosaria cf. affinis Reuss, Nodosaria sp., Robulus (?) sp., Guttulina trigonula (Reuss), Bulimina reusi Morrow, Ceratobulimina sp. (after S. Nagao) The present writer (1957a) reported, as the result of his study of the foraminifers which he had collected from the Nemuro group in the border of Kushiro and Tokachi Provinces, that this group may be tentatively assigned to Upper Hetonaian ( . 'Maestrichtian) in age, he also suggested, on the basis of the existence of planktonic foraminifera-Globigerina cf. triloculinoides Plummer-and the assemblage of foraminifers, that this group possibly corresponds to Rzehakina-Spiroplectammina zone (Paleocene) ( H. D. Hedberg and A. Pyre, 1944) in the Santa Anita formation of Venezuela, S. A. The present writer also reported (1958d) that, according to the microfossils and stratigraphical relations put together, the foraminiferal assemblages collected from the Nemuro group which crops out in the Hamanaka district probably range from Maestrichtian to Danian in age, despite the fact that he could discover no planktonic foraminifers among them. Recently, K. Asano reported (1960) his discovery of some species of planktonic foraminifers from the Ch<>boshi formation of the Nemuro group at Chi'>boshi, and mentioned that this fauna consists of three of the species that were common to the fauna of type Danian, namely, Globigerina cf. triloculinoides Plummer,. G. daubjergensis Bri)nniman and G. pseudobulloides Plummer, concluding that some horizons of the Chi")boshi formation belong to Danian. He reaffirmed this fact in his special address at the 25th Anniversary Meeting of Paleontological Society of Japan, held in Jan. 1961. The planktonic foraminifera, Globigerina, in the Nemuro group reported by the present writer (1957a) from the Hombetsu district and by K. Asano ( 1960) from the Hanasaki Peninsula, is considered to be most important in determining the geological age of this group.. The biostratigraphical studies of the planktonic foraminifera from. the Lower Tertiary and Upper Cretaceous strata have been carried out by many students, who have subsequently recognized a sharp faunal break between these strata. Among those studies, Tappan. a fundamental one was made by A. R. Loeblich, Jr. and H.. (1957) , who established the planktonic foraminiferal sequences from the. Upper Cretaceous to Lower Tertiary, as Table l. The Globigerina collected from the Nemuro group is small in the number of species and individuals .;. mor~over,. no. other planktonic forms have yet been discovered from this group. But if this qlobige. --- 19-.

(10) The Cretaceous-Tertiary Boundary in Eastern Hokkaido, Japan. rina is correlated with Globigerina Assemblage ( Danian) as mentioned above, it is possible that the Nemuro group corresponds to the Maestrichtian Chalk Tuff formation or Paleocene in age. It is a well-known fact that there is a stratigraphical unconformity between the Nemuro group which has been correlated with Upper Cretaceous and the Urahoro group which has been assigned to lowermost Tertiary ( .~late Eocene-early Oligocene). Moreover, it has been recognized that the Beppo formation, the lowermost member of the Urahoro group, is the basal conglomerate, and that mega-and microfaunistically there is a considerably sharp faunal break between these two groups. Consequently, the Upper Cretaceous-Lower Tertiary Boundary has hitherto been placed between these two groups in the Kushiro coal field and a.djacent areas. In the Ishikari coal field, also, the lowermost Tertiary Ishikari group has been considered to belong to Eocene <J.t the earliest. The stratigraphical relation between the above-mentioned group <J.nd the Hakobuchi group which has been assigned to Upper Cretaceous (.-.:Campanian-Maestrichtian) is unconformable, and no one has ever assumed the existence of Paleocene strata between these two groups (S. Yoshida et al., 1959). In addition, according to the micropaleontological study by Y. Takayanagi (1959a, b, 1960) no planktonic foraminifera has been discovered from the Upper Hctonaian series in the Ishikari co2.l field and the other areas in central Hokkaido, nor any foraminiferal fossils have been collected from the uppermost part of the above-mentioned series. No foraminifers have been collected either from the next lowermost Tertiary Horokabetsu formation or from the lowermost Noborikawa formation which unconformably overlies the Upper Hetonaian series in the Ishikari coal field. However, K. Asano (1952, 1954, 1958) and H. Ujiie and H. Watanabe (1960) reported the foraminiferal fauna from the lshik ari and Poronai groups, concluding that the geological age of the Poronai group ranges from Narizian ( Upper Eocene) to Refugian (Lower Oligocene) . Table I.. PLANCTONIC FORAMINIFERAL SEQUENCES ESTABLISHED BY LOEBLJCH & TAPPAN ( 1957). AGE L'. r,ocene. STAGE. I. Planktonic Foraminifer al Assem-1 Planktonic Foraminiferal faunal zones blage. I y prestan . I. Gtobigerina-Globorotalia. 1. ---·--..c.~---- · Paleo- , cene. Landnian. I Globorotalia rex. Truncorotal01des Assemblage. - -- - Globigernw·keeled Globorotalia Assemblage. 1------- -------- ---\. . Daman. -~ Gl b'. . ° tgerma. A bl .s sem age. _C_r_et-a----;~!-hrv-ft-a-es--t-ri-c~,- Globotr~ncana Assembl~~-ceous. zone. ,·-G-lo_b_o-ro-t-al-ia-.--I--:G-lo-b-or_o_ta-l-ia- ve- l-asc-9ensis-G. acutaGlob1germa sfnralzs subzone 1 - - ---- - - - -- -- -- - 1 angulata Globorotalia pseudobulloides zone -- - ~ubzone - ·- - - Globorotalia compressaGtobigerinoides daubjergensis zone. I. Globotruncana zone. - - - - ---. tan. According to the foraminiferal studies of the above-mentioned paleontolo.l{ists, there seems to be a sharp faunal change at the Upper Cretaceous-Lower Tertiary Boudary. -- 20-.

(11) Saburo YOSHIDA. In the report area of eastern Hokkaido, the relation between the Nemuro group and the Urahoro group is similar to that between Upper Cretaceous and Paleogene in the Ishikari coal field. As is known from the foregoing paragraphs, the geological age of the Nemuro group inferred from planktonic foraminifers differs from the age determined by megascopic fossils, as follows : (1) According to the global correlation of planktonic foraminifers, the Nemuro group, or at least part of it, is possibly correlated with Paleocene (Danian). (2). Megafaunistically, the Nemuro group belongs to Cretaceous, and its greater part. corresponds to Upper Hetonaian (.·Maestrichtian). However, it must be noted here that the age of the Nemuro group has been discussed with little attention paid to the fossil-bearing horizons in spite of the fact that the thickness of the group locally attains to more than 3, OOOm. The present writer previously reported at the meeting of the Paleontological Society of Japan that the Nemuro group distributed in eastern Hokkaido can be divided, by the characteristic occurrence of megascopic fossils, into the following three zones ;. Inoceramus zone representing the lower part, Ammonite zone m the middle part, and the upper part represented by the zone of other molluscan fossils. Also, as the result of the study of foraminiferal fossils, the writer reported that the foraminiferal fauna of the Nemuro group in the Monshizu·Kombumori district can be classified into three fossil assemblages. Table II shows the relation between the stratigraphic sequence Table Stratigraphic. Sequence. Foraminiferal. II. Assemblage. _I_. Megafossil. zone. ---. Sarukiushi. formation. Chippomanai. formation. Oshamappu. formation. Shiomi. formation. Semposhi Monshizu. Upper. Assemblage. Other. formation. Middle. Assemblage. Ammonite. zone. formation. Lower. Assemblage. Inoceramus. zone. and the divisions by megascopic fossils and foraminifers.. Mollusca. zone. Then the writer preliminarily. reported* that the above·mentioned Inoceramus zone and Ammonite zone may correspond to Upper Cretaceous, and the Mollusca zone can be correlated with Lower Tertiary. In this report, however, on the basis of the zoning by megascopic and foraminiferal fossils, the lithologic character and the stratigraphic relation, the writer attempted a correlation of the Nemuro group distributed in many districts of eastern Hokkaido, as shown by Chart II.. *. Discovery of Pachydiscus subcompressus obsoletus Matsumoto from the Upper Cretaceous of Eastern Hokkaido and Its Geological Significance (An address at the Meeting of Paleontological Society of Japan, held in Dec. 1958). -21-.

(12) The Cretaceous-Tertiary Boundary in Eastern Hokkaido, Japan. Next, the boundary between the Tertiary and the Cretaceous in the respective districts will be discussed. The Nemuro group distributed near the provincial border between Tokachi and Kushiro, especially in the Hombetsu and Tokomuro districts, was divided into the Kappei formation in the lower part and the Kawaruppu formation, or Tokomuro formation, in the upper part, by K Mitani and others ( 1959) and Y. Oda and others (1959).. The present writer discovered Globigerina cf. triloculinoides Plummer in the. Kappei formation and the Kawaruppu formation ; hence, he has come to hold a view that the Nemuro group of this district may belong to Paleocene, although it was previously assigned to Upper Hetonaian by attaching importance to megascopic fossils. On the other hand, megascopic fossils in the Nemuro group of this border area bear a close resemblance to those of the Upper Hetonaian in the Ishikari coal field, central HokkaidG. This resemblance, especially the occurrence of Inoceramus, is an important and and as well a difficult problem in the discussion of the age of the Nemuro group of this area. Because, Inoceramus which has been considered to disappear during the Maestrichtian stage at the end of Cretaceous occurs in the horizon idential with the horizon from which the writer discovered Globigerina of Danian type. Lately, Kopp, K 0. (Tokunaga, S., 1960) has reported the abundant occurrence of Inoceramus in the belonging to Danian and Eocene in the districts around the Mediterranean Sea, and such a fact may be found in the area of this report.. An interpretation of the. above fact will be attempted below, in the discussion of a similar fact observed in the Choboshi formation of Hanasaki Peninsula. From the Chiiboshi formation of the Nemuro group distributed in the vicinities of ChOboshi and Ochiishi in Hanasaki Peninsula, K. Mitani and others (1958) reported Neophylloceras hetonaiensis Matsumoto, although they could collect no more than one individual specimen, and the present writer (1960a) collected many Ammonites of unknown species from the same formation. On the other hand, pl:mktonic foraminifers of Danian type were also discovered by K. Asano ( 1960). These fossil evidences are making the age determination of the ChOboshi formation difficult. The fact that the above-mentioned fossils indicating two different ages are found in the idential -formation can be interpreted in various ways as follows : (a). The Choboshi formation is a transitional formation between Upper Cretaceous. and Lower Terti2.ry, hence intermixture of fossils of two different ages can happen. (b) ( i). If the Choboshi formation is assigned to Paleocene ( Danian) The period inhabited by the fossils which are believed to have disappeared during Upper Cretaceo us-such as Ammonite - is inferred to extend at le2.st up to Danian.. ( ii). Ammonites and Inoceramus* are reworked fossils from the beds belonging to. * In addition to Ammonites, the present writer found bwceramus in the nodules contained in the Choboshi formati on which is exposed on the coast of Bokkiri -iso Bay at Ochiishi. -. 22-.

(13) Saburo YOSHIDA. Upper Cretaceous, older than the Choboshi formation. (c). If the Ch.-)boshi formation is assigned to Upper Cretaceous (Maestrichtian) , the. age of the planktonic foraminifers of Danian type becomes as old as Maestrichtian. (d). The CMboshi formation as defined by Mitani and others can be subdivided. into the part belonging to Upper Cretaceous and the part belonging to Lower Tertiary. The idea of transitional formation (a) : In order to establish a period between Cretaceous and T ertiary, like Hay (1893)* who used a term Permocarboniferous** for a transitional. ~formation. between Carboniferous and Permian. available data are very. few. Besides, judging from the characteristics of fossils, some other interpretation than the above may be more appropriate. Interpretation ( i) of ( b) : The present writer has mentioned the study of Kopp, K. 0. (Tokunaga, S., 1960) who reported Inoceramus from the Tertiary beds. It is a. general belief that occurrence of Ammonites is limited to Cretaceous, and applying Kopp's view to this rase is hardly acceptable in the present stage of our paleontological knowledge. Also, no positive evidence has been available to verify the interpretation ( ii) of (b) , i. e., Ammonites and Inoceramus collected from the Choboshi formation are reworked fossils.. As far as the present writer's observation on the mode of occurrence of. Ammonites and Inoceramus (1960a) are concerned, it cannot be confirmed that these are reworked fossils.***. J. Hofker reported(1959b) the megascopic fossils in the Maest-. richtian Tuff Chalk as reworked · fossils, and assigned the Tuff Chalk to Danian on the basis of planktonic foraminifers.. However, such an interpretation does not seem to be. applicicable to Ammonites and Inoceramus of the Choboshi formation. The writer's knowledge may not suffice to discuss the problem of the type localities in Europe, but the writer would admit that the Maestrichtian Tuff Chalk, which contains planktonic foraminifers which are identical with those at the type locality of Danian, is characterized by Ammonites and other faunas of purely Mesozoic type. This fact is a very important problem in age dete1mination of the Nemuro group. Interpretation (d) : When the sedimentary condition of the CMboshi formation which was defined by K. Mitani and others (1958) is studied, a large scale slumping structure is observed, as anybody would recognize at Chuboshi, Kombumori and on the Ochiishi coast. It is probable that the Choboshi fo :··...;tion is a Paleocene deposit and the beds belonging to Upper Cretaceous and containing Ammonites and Inoceramus fell, as slumping blocks, into the younger Choboshi forn' ation due to submarine sliding.****. *. Moore, R. C., 1940. The term is used in the same sence as Permian. Some people use the term Permo-Carboniferous. *** The Ammonites discovered by the present writer were contained in the mudstone, 2 to 3 c1n thick, in the alternation of mudstone and sandstone, but no planktonic foraminifers were found in this mudstone. **** With regard to the cause of this slumping, K. Mitani and others (1958) consider an igneous activity by which dole rite was intruded into the Nemuro formation.. **. -. 23-.

(14) The Cretaceous-Tertiary Boundary in Eastern llokkaidii, Japan. Consequently, the beds defined as the Ch<>boshi formation should be subdivided into the members corresponding to Paleocene and the members assigned to Upper Cretaceous. This interpretation may not be impossible, including the possibility of an unconformity* proposed by. Mitani and others (1958) between the. underlying Nemuro formation. of conspicuous. Choboshi formation and the. However, as has been mentioned before, the existence. slumping structure of the Choboshi formation would. imp~de. the. subdivision of the formation into the two members representing two different ages. In fact, subdivision of the formation, when viewed externally, is extremely difficult. As has been stated so far, the Nemuro group distributed in Hanasaki Peninsula partly includes the beds obviously assignable to. Paleocene in view of planktonic. foraminifera, but they are hardly distinguishable from Upper Cretaceous on the basis of the megafossil evidence. Thus, in the present stage of our knowledge, the Nemuro group cannot serve as a geological boundary between Cretaceous and Tertiary.. Pachydiscus subcompressus obsoletus. Matsumoto,. which was discovered by the. present writer (1960a) from the Nemuro group** exposed at Esashito of the Hamanaka district, is an index fossil of Upper Hetonaian. On the basis of the marked slumping structure observed in the Hamanaka formation, as well as of its lithology and fossils*** the writer correlated the Hamanaka :formation with the Chr>boshi formation.**** No planktonic foraminifers have been found in the area of this report, and benthic foraminifers are very few.. Only one species of Ammonite was collected from a. calcareous nodule, and it cannot be defined whether it is a reworked fossil or not. The coarse-grained tuffaceous sandstone at Pomporoto of the Hamanaka district, from which the writer discovered Gaudryceras aff. kayei (Forbes) (1958c, l960a) *****, is a large block of a stratified bed which appears to be in fault-like contact with the surrounding muddy rocks in which slumping structure is developed ; so this sandstone may be a slumping block that has bet.I f.c'shed into the muddy rock. At this locality, planktonic foraminifers are not found either ;n the Ammonite-bearing coarse-grained sandstone or in the surrounding muddy rock, ;:nd benthic foraminifers are very few. Thereupon, the correlation of the Hamanaka formation with the Chiiboshi formation of Hanasaki Peninsula was made on the basis of megascopic fossils and lithologic character. Through detailed studies in the future, the Hamanaka formation may be divided. into. the. Ammonite bearing coarse-grained sandstone and the mudstone. members.. * Mitani and others inferred an unconformable relation between the Choboshi formation and the underlying Nemuro formation, for the reason that the former contains pebbles of dolerite intruded into the latter. ** Harnanaka formation *** Megascopic fossils from the Hamanaka formation in this vicinity occur in the same loca lity (No. 57061501) as Ammonites, anrl have not been found in other localities. **** The writer was unable to trace the relation between the Nemuro group of Hanasaki Peninsula and that of the report area, because the intermediate area was covered by Ouarternary beds. ***** According to identification by Prof. Tatsuro M atsumoto. -24-.

(15) Saburo YOSHIDA. As has been mentioned before, the writer divided the Nemuro group of the MonshizuKombumori district into three faunal zones, but. Prof.. T.. Matsumoto has lately. discovered Ammonites* from the writer's Upper zone** On the other hand, the writer, in his study of foraminiferal fossils in the Nemuro group of the reporl area, established three assemblages, Upper, Middle and Lower. However, a distinct quantitative change of foraminiferal fossils can be recognized between the Shiomi formation and the Chippo· manai formation, so the writer now holds a view that the boundary between the Upper zone and the Middle zone of the previously established faunal zones should be placed between the Chippomanai formation and the Shiomi formation. Thus, he attempted a new correlation, as shown in Chart II, inferred from the fossils and the mode of sedimentation of the Nemuro group of this report area and from the existence of dolerite intruded into the base of the Shiomi formation . In spite of the abundant occurrence of foraminiferal fossils*** in the Nemuro group of this area, none of the planktonic species indicates Tertiary or Cretaceous age. Therefore, the writer thinks that the boundary between the Tertiary system and the Cretaceous system of this area should be drawn, on the basis of megascopic fossils, between the Urahoro group and the Nemuro group, as was pointed out by Y. Sasa and I. Hayashi (1952) and approved by many others. As the foregoing paragraphs reveal, the Nemuro group distributed in eastern Hokkaidu yields planktonic foraminifers which obviously indicate the age of Paleocene (Danian) in the present stage of our paleontological knowledge, as is known in two district****, although the number of individuals is small.. From the corresponding horizons and. from the beds above, megascopic fossils***** showing elements of the Cretaceous system are found. Therefore, even though part of the Nemuro group may be separated as Danian in the future, the writer tentatively assigned the age of this group to Upper Cretaceous.. T. Matsumoto (1942-1943, 1953) summarized the Cretaceous system of Japan and divided the Hetonaian corresponding to Upper Cretaceons into the older stage and the younger stage, on the basis of the biostratigraphic study of Ammonites and. Inoceramus. H. Takeda and W. Hashimoto (1949) restudied the mode of appearance of new species and disappearance of species of the preceding period, and proposed a term Hetonaian (. 'Maestrichtian) for Matsumoto's younger stage of the Hetonaian. From the deposits corresponding to this newly proposed Hetonaian are reported fossils of Ammonites, Inoceramus and other molluscs.. According to Y. Takayanagi ( 1960) .. the beds belonging to Upper Hetonaian in central Hokkaidii do not yield any planktonic or benthic foraminifers****** which would characterize the Upper Cretaceous system.. *. Oral communication of Prof. Matsumoto.. ** Shiomi formation.. *** **** *****. ******. Especially the Semp;;shi formation yields much more foraminife rs than othe•· formation do. Hombetsu district and Hanasaki Peninsula. Especially those of pelecypods and gas tropods. Some foraminifers were found but none of them was Gtobotruncana which indicates Cretaceous. age.. -. 25 -.

(16) The Cretaceous-Tertiary Boundary in Eastern Hokkaido, Japan. Throughout eastern Hokkaido, the Nemuro group shows a cycle of sedimentation which began with the andesitic effusive rock facies, succeeded by the facies of thick mudstone, and ended in the beds of a regression period consisting chiefly of conglomerate (Hashimoto, W., 1958). The upper part of the Nemuro group is a deposit of the regression period during which the large scale submarine sliding took place. It contains fossils indicating the Upper Cretaceous age, such as Ammonites, Inoceramus and other molluscs, coral, etc. It also yields benthic foraminifers in abundance, and some planktonic foraminifers, Globigerinidae, of Danian type. However, Globotruncana indicating Upper Cretaceous age has not been found as yet.. The present writer thinks that the. sedimentational stage of the Nemuro group having such characteristics as mentioned above corresponds to the Hetonaian (.' Maestrichtian) newly proposed by Tak eda and Hashimoto (1949) or somewhat ranges to the younger period.. And, in order to. avoid confusion to be caused by the usage of the term Hetonaian by Matsumoto and the new term proposed by Takeda and Hashimoto, the present writer would like to propose a new term "Nemuroan" for the sedimentational stage of the Nemuro group, as shown by Table Ill. Table Ill.. - -- - ----,---- - -- -- -T . Matsumoto. H. Takeda o.nd. S. Yoshida. European. W. Hashimoto. (1942-1943, 1953). ( 1961). (1949). Upper Hetonaian. Hetonaian. J. IMae:;richtia~-~--. Nemuroan. Hetonaian. ------~ -~:::;m~::onaian --~~-~~ ~- -~~·····------- --~[---~=---:-~- c~mpanian-----~ ~ Urakawan. -~~~kawan:-. I·······. ·-··. ·- ~ ~ ,. ~ ~ . -Sant;~j~~- - ~ ··-· - -· ~- - ···- · - · u. Lower Urakawan. Coniacian ... ~~ .... Upper Gyliak ian Gyliakian. -. - --- -- -. ·-- --til. Tnro~i~ _ _ . ~ .. Cenomanian · -- - - ' - -·-- -. Lower Gyli akian. ··-1. The "Nemuroan" denotes the stage during which the Nemuro group was deposited, with the Nemuro group distributed in eastern Hokkaido as the type locality. It contains megascopic fossils common with the Upper Hetonaian. The Nemuroan has another feature common with the Upper Hetonaian in central Hokkaido, i. e., the absence of. Globotruncana. The only difference is the occurrence of planktonic foraminifers of Danian type in the upper part. For the time being the writer assigned the Nemuroan stage to Uppermost Cretaceous- -even though it may be partly included in the Tertiary system in the near future. In the. Far East, a hiatus has been inferred between. Cretaceous and. Tertiary. (Vershchagin, V. N., 1957) , but pertaining to the Nemuro group, which was deposited -. 26-.

(17) Saburii YOSHIDA. during the Nemuroan stage newly proposed by the present writer, there remain many questions unanswered, and the necessity of further study in detail is keenly felt. References Allard, P. L., et a l., 1959, Les foraminifiires et le. CnHace supMieur. fran~ais,. mise au point et. donnees nouvelles, 84e Congr. Soc. sav., pp. 591-660, 2 text-figs, l table. Asano, K., 1950a, Upper Cretaceous Foraminifera from Japan, Pac. Sci., vol. 4, no. 2, pp. 158-163, pl. I. Asano, K., 1950b, Cretaceous Foraminifera from Teshio, Hokkaidii, Short Pap., Ins!. Geol. Pal., Tohoku. Univ., no. 2, pp. 13- 22, pl. 3. Asano, K., 1950c, Outline of the Cenozoic Foraminifera from Hokkaidii, Part I ( in Japanese),. Shinseidai no Jl.enkyu (The Cenoz. Res.) , no. 5, pp. 73-75, 10 text-figs. Asano, K., 1950d, Cretaceous Foraminifera from the Futaba District. (Abstract) (in Japanese) , ].. Geol. Soc. japan., vol 56, no. 656, p. 289. Asano, K., 1952, Paleogene Foraminifera from the Ishikari and the Kushiro Coal Fields, Hokkaidii,. Short Pap., Ins!. Geol. Pal.. T ohoku Univ., no. 4, pp. 23-46, pis. 3-5. Asano, K., 1954, Foraminiferal Sequence in the Paleo-Ishikari Sea, Hokkaidii, Japan ( in Japanese with English Abstract), ]. Geol. Soc. japan., vol. 60, no. 701, pp. 43-49, text-figs. 1-5. Asano, K., 1955, On the Correlation of the Paleogene Deposits of the Ishikari and the Kushiro Coa l Fields (in .Japanese) , Shinsei.dai no Kenkyii ( The Cenoz. Res.), no. 21, pp. 13-15, 2 text-figs. Asano, K., 1960, Tertiary Deposits of Japan and Their Planktonic Fossil Foraminifers ( in Japanese),. Yfikochu (Foraminifera), no. 11 , pp. 64-69, 2 tables. Avnimelech, M., and Reiss, Z., 1954, On the Upper Cretaceous and Tertiary Stratigraphy of a Boring near Beth-Covin (Israel), Bull. Res. Counc. Israel. vol. 3, no. 3, pp. 171-176. Bandy, 0. L., 1951, Upper Cretaceous Foraminife ra from the Carlsbad Area, San Diego County, California, ]. Pal., vol. 25, no. 4, pp. 488-513, pis. 72-75, 2 text-figs. Beckmann,. J. P., 1957, Chiloguembelina Loeblich and Tappan and Related Foraminifera from the. Lower Tertiary of Trinidad, B. W. I., Bull. U. S. Nat. Mus., 215, pp. 83-96, text- figs . 14-16, pl. 21. Berryhill, H . L., Jr., Briggs, R. P., and Glover, L. III., 1960, Stratigraphy, Sedimentation, and Structure of Late Cretaceous Rocks in Eastern Puerto Rico (Preliminary Report), Bull. Amer. Ass. Petrol.. Geol., vol. 44, no. 2, pp. 137-155, 13 text-figs. Bolli, H. M., 1951, The genus Globotruncana in Trinidad, B. W. I., f. Pal., vol. 25 , no. 2, pp. 187199, pis. 34-35, 1 text-figs. Bolli, H. M., 1952, Note on the Cretaceous-Tertiary Boundary in Trinidad, B. W. I., ibid., vol. 26, no. 4, pp. 669-675. Bolli, H. M., 1957a, The genera Pra.eg lobotruncana, Rotalipora, Globotruncana, and Abathomphalus in the Upper Cretaceous of Trinidad, B. W. I., Bull. U. S. Nat. Mus., 215, pp. 51-60, text-fig. 10, pis. 12- 14. Bolli, H . M., l957b, The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Li zard Springs Formation of Trinidad, B.. w.. I., ibid., pp. 61-82, text-figs. 11-13, pis. 15-20.. Bolli, H. M., Loeblich, A. R., Jr., and Tappan, H., 1957, Planktonic Foraminiferal Families Hantkeninidae, Orbulinidae, Globorotaliidae, and Globotruncanidae, ibid., pp. 3-50, text-figs. 1-9, pis. 11. Chaney, R. W., 1951, On the Metasequoir (in Japanese) . Tanko-Gijutstt (Hokkaido Coal Min. Techno/.) , - 27 -.

(18) The Cretaceous-T e rtiary Boundary in Eastern Hokkaido, Japan vol. 6, no . 2, pp. 2·-7. Cita, M. B., 1954, II Daniano in Italia, Ace. Nazio, Lincei, ser. 8, vol. 18, fasc. 2, pp. 201-207, text-figs. 1-2. Cita, M. B., 1955, The Cretaceous-Eocene Boundary in Italy, Proc. 4th World Petrol. Congr., sec. l/D, Rep. 2. Coal Min. Ass. Jap., Hokkaidii Branch, 1953, The Kushiro Coal Field (in Japanese), Coal Fields of. Hokkaid6, no. 2, 160 pp., 73 tables. Cushman, }. A., 1926, The Fora minifera of the Velasco Shale of the Tampico Embayment, Bull. Amer.. Ass. Petrol. Geol., vol. 10, pp. 581-612, pis. 15-21. Cushman, T. A., 1929, A Late Tertiary Fauna of Venezuela and other Related Regions, Contr.. Cushmarl Lab. Foram. Res., vol. 5, pt. 4, pp. 77-101, pis. 12- 14. Cushman, ]. A., 1930, Notes on Upper Cretaceous Species of Vaginulina, Flabellina and Frondicularia from Texas and Arkansas, ibid., vol. 6, pt. 2, pp. 25-38, pis. 4- 5. Cushman, J. A., 1931, A Preliminary Report on the Foraminifera of Tennessee, Bull. Tenn. Div.. Geol., no 41, pp. 1-62, pis. 1-1 3. Cushman, J. A., 1936a, Notes on Some American Cretaceous Frondicularias, Contr. Cushman Lab.. Foram. Res., vol 12, pt. 1, pp. 11- 23,. pis. 3-4.. Cushman, J. A., 1936b, Some American Cretaceous Species of El/ipsonodosaria and Chrysalogonium,. ibid., vol. 12, pt. 3, pp. 51-55 , pl. 9. Cushman, l. A., 1937, Some Notes on Cretaceous Species of Marginulian, ibid., vol. 13, pt. 4, pp. 91-99, pis. 13-14. Cushman, J. A., 1938a, Additional New Species of American Cretaceous Foraminifera, ibid., vol. 14 , pt. 2, pp. 31-50, pis. 5-8. Cushman, J. A., 1938b, Some New Species of Rotaliform Foraminife ra from the American Cretaceous,. ibid., vol. 14, pt. 3, pp. 66-71, pis. 11-12. Cushman, .J. A., 1940a, American Upper Cretaceous Foraminifera of the Family Anomalinidae, ibid., vol. 16, pt. 2, pp. 27-40, pis. 6- 7. Cushman, J. A., 1940b, Midway Foraminifera from Alabama, ibid., vol. 16, pt. 3, pp. 51-73, pis. 9--12. Cushman, J. A., 1940c,. American Upper. Cretaceous. F oraminifera of the. Genera. Dentalina a nd. Nodosaria, ibid., vol. 16, pt. 4, pp. 75- 96, pis. 13-16. Cushman, J. A., 1911, American Upper Cretaceous Foraminifera Belonging to Robulus and Related Genera, ibid., vol 17, pt. 3 , pp. 55- 69, pis. 15-16. Cushman, J. A., 1944a, The Foraminiferal Fauna of the Type Locality of the Pecan Gap Chalk,. ibid., vol. 20, pt. 1, pp. 1-17, pis. 1-3. Cushman, J. A., 19Hb, A Paleocene Foraminiferal Fauna from the Coal Bluff Marl Member of the Naheola Formation of Alabama, ibid., vol. 20, pt. 2, pp. 29-50, pis. 5-8. Cushman, ). A., 1944c, Foraminifera of the Lower Part of the Mooreville Chalk of the Selma Group of Mississippi, ibid., vol. 20, pt. 4, pp. 83-96, pis. 13-14. Cushman, J. A., 1946, Opper Cretaceous Foraminifera of the Gulf Coastal Region of the United States and Adjacent Areas, Prof. Pap. U. S. Geol. Surv., no. 206, 241 pp., 66 pis., 1 table. Cushman, ]. A, 1947a, Foraminiferal Evidence for the Age of the Velasco Shale of Mexico and Lizard Springs Marl of Tr·inidad, ]. Pal., vol. 21, no. 6, p. 587. Cushman, J. A., 1947b, A Foraminiferal Fauna from the Santa Anita Formation of Venezuela, Con.tr.. Cushman Lab. Foram. Res., vol. 23, pt. 1, pp. 1-18, pls. 1- 4. -. 28 ---.

(19) Saburu YOSHIDA Cushman, J. A., 1949, The Foraminiferal Fauna of the Upper Cretaceous Arkadelphia Marl of Arkansas, Prof. Pap. U. S. Geol. Surv., no. 221-A, pp. 1- 10, pis. 1-4. Cushman, J. A., 1951, Paleocene Foraminifera of the Gulf Coastal Region of the United States and Adjacent Areas, ibid., 232, pp.. 1-73, pis. 1-24.. Cushman, ]. A., and Jarvis, P. W., 1928, Cretaceous Foraminifera from Trinidad, Cont1·. Cushman. Lab. Foram. Res., vol. 4, pt. 4, pp. 85- 103, pis. 12-14. Cushman, ]. A., and Ponton, G. M., 1932, An Eocene Foraminiferal Fauna of Wilcox Age from Alabama, ibid., vol. 8, pts. 3-4, pp. 51-72,. pis. 7- 9.. Cushman. ]. A., and Parker, F. L., 1935, Some American Cretaceous Bu/iminas, ibid., vol. 11, pt. 4 , pp. 96-101, pl. 15. Cushman, J. A., and Parker, F . L., 1936, Ditto, ibid., vol. 12, pt. 2, pp. 39-45, pls. 7-8. Cushman, ]. A., and Garrett, ]. B., 1939, Eocene Foraminifera of Wilcox Age from Woods Bluff, Alabama, ibid., vol. 15, pt . 4, pp. 77-89, pis. 13-15. Cushman, J. A., and H edberg, H. D., 1941, Upper Cretaceous Foraminifera from Santander del Norte, Colombia, S. A., ibid., vol. 17, pt. 4, pp. 79- 100, pis. 21-23. Cushman, ]. A., and Todd, R., 1943a, The Genus Pullenia and Its Species, tbirl.,. vol. 19, pt. l, pp.. 1-23, pis. 1-4. Cushman, ]. A., and Todd, R.. 1943b, Foraminifera of the. Corsicana Marl, ibid., vol. 19, pt. 3,. pp. 49-72, pis, 9-12. Cushman, .f. A., and Goudkoff, P. P., 1944, Some Foraminifera from Upper Cretaceous of California, ibid., vol. 20, pt. 3, pp. 53- 64, pis. 9-10. Cushman,. J. A., and. I~enz,. H. H., 1946, The Foraminiferal Fauna of the Lizard Springs Formation. of Trinidad, B. W. I., Spec. Pub. ibid., no. 18, 48 pp., 8 pis., 1 map. Cushman, ]. A., and Todd, R., 1946, A Foraminiferal Fauna from the Paleocene of Arkansas, Contr. ibid., vol. 22, pt. 2, pp. 45-65, pls. 7-11. tem Dam, A., 1947, Reviews,]. Pal., vol. 21, pp. 187-188. tern Dam, A., and Sigal, ]., 1950, Some Ne ·.v Species of Foraminifera from the Dano-Montian of Algeria, Contr. Cushman Founi. Foram. Res., vol. 1, pts. 1-2, pp. 31-37, pl. 2. Drooger, C. W.,. 1952, Foraminifera from Cretaceous-Tertiary-Transitional Strata of the Hodna. Mountains, Algeria, ibid., vol. 3, pt. 2, pp. 89-103, pis. 15-16. Dunnington, H. V., 1955, Close Zonation of Upper Cretaceous Globigerinal Sediments by Abundance Ratio of GtobJtruncana Species Group, Micropaleontology, vol. 1, no. 3, pp. 207- 2l9, tex t-figs. 1-8, table 1. End<>. S., 1925, On the Geology of Shikotan Islands (in Japanese), ] . Geogr. Soc. Toky o, vol. 37, pp. 180-184. Egu chi, M., 1951, Mesozoic Hexacorals from japan, Sci. Rep. T<lhoku Univ., 2nd Ser., vol. 24, pp. 1- 96, pis. 1-28. Fal!ot, P., et al., 1958, El Cretaceo Superior del Sur de Caravaca (Provincia de Murcia), Not.. Comun. , num. 50, pp. 283-298, pl. 1, text- figs. 1-3. Fox, S. K., Jr.. 1954, Cretaceous Foraminifera from the Greenhorn Carlile and Cody Formations South Dakota, Wyoming , Prof. Pap. U. S. Ceo/. Sur., no. 254-E. pp. 97-124, pis. 24- 26. Frizzell, D. L., 1954, H a ndbook of Cretaceous Foraminifera of Texas, Rep. Invest. Un iv. Tex., Bur.. Econ. Geol., no. 22, 232 pp., 21 pis., 4· tables. Fuiie, T., 1957, On the Myarian Pelecypods of Japan, Pt. I, Summary of the Study of the Genus -. 29-.

(20) The Cretaceous-Tertiary Boundary in Eastern Hokkaido, Japan. Mya fr om Hokkaid o, J. Fac. Sci., Hokkaido Univ., 4th Ser., vol. 9, no 4, pp. 381-413, 8 pis., 4 text- figs. Fujiwara, T., 1959,0n the Igneo us Activities and the Ore Deposit at Hamanaka Area, Hokkaidii ( in Japanese), ]. Jap. Ass.Min. Petrol. Econ., Geol., vol. 43, n o. 4. Fujiwara, T., and Mitani, K., 1959, Explanatory Text of the Geological Map of Japan, Scale 1 : 50,000, Nosappu Sheet (in Japanese with English Abstract), Geol. Surv. Hokkaidii, 46 pp., 32 pls., 5 text-figs., 1 table, 1 map. Fukada, A., 1953, Cretaceous Amn1onites from Barasan Cape, Akkeshi, Kushiro Province(i n Japanese) ,. Chishitsu Yoho (B ull. Ceo!. Comm. HokkaidiJ), no. 21. Fukuta, 0., 1957,. Upper Cretaceou s Foraminifera from the Rumoi Coal. Field, Hokkaid o, Japan,. Rep. Geol. Surv. Japan , n o. 172, pp. 1- 18, pl. 1 text-fig ., 3 tables. Graham, J. J., and Classen, W. J., 1955, A Lower Eocene Foraminiferal Faunule from the Woodside Area , San Mateo County, California, Contr. Cushman Found. Foram. Res., vol. 6, pt. 1, pp. 138, pis. 1-6. Grimsdale, T. F., 1947, Upper Cretacecus Foraminifera. A Criticism, J. Pal., vol. 21, no. 6, pp.. 586-587. Hanzawa, S., 1953, Im portance of Planktonic Foraminifera ( in Japanese) , Yfikochii. ( Foraminif era), no. 1, pp. 16-24, 1 table. H anzawa, S., 1956, The Problem of the " Danian"- a Review, ibid., no. 5, pp. 49-60. Hasegawa, K ., and Fujiwara, T ., 1959 , On the Alkali Basalt in the Igneous Rocks of Nemuro Peninsula, Hokkaid<> (i n Japanese with English Abst ract), Rep. Geol. Surv. Hokkaido, no. 21, pp. 1-16, pis. 1-4, 9 text-figs. Hasegawa, K., and Mitani, K., 1959, Explanatory Text of the Geological Map of Japan, Scale 1 : 50,000, Nemuro-hokubu Sheet ( in Japanese with English Abstract), Geol. Surv. Hokkaidii, 27 pp., 13 pis., 5 text-figs., 1 table, 1 map. Hashimoto, W., 1955,. Geology a nd Underground Resources of T okachi Province (in Japanese),. Pub. Tokachi Ass. Accel. Synth. Devel., 53 pp., 1 table, 1 map. Hashimoto, W., 1956, Mesozoic Stratigraphy of Hokkaid<-, (in Ja panese), Koki-Chiiseikai no Kenkyi1. (Late Mesez. Res.), n o. 3. pp. 1-9, text-fig. I. Hashimoto, W., 1938a, Explanatory Text of the Geological Map of Hokkaid<> ( Geology of Hokkaidc,), Scale 1: 200,000 (in J apanese) , Geol. Surv. Hokkaido, pp. 1-26, 1. text-fig.. H ashimoto, W., 1938b, Considerat io ns on the Geological H istory of the Yezo-Saghalien Geosynclinal Area (in Japanese with English Abstract), Jubilee Publ. Cornmem. Prof H. Fujimoto's 60th Birthday, pp. 101-112, text-figs. 1-4, 1 table. H ashimoto, W., 1958-1939, Geology of Hokkaid<, (in Japanese), Chikashigen (Underground Reso.) , nos.. 1 ~5,. pp. 26-28, 18- 24 , 13-20, 9-15, 26-32.. Hashimoto , W., et aL, 1960, Several Problems of the Cretacecus-Tertiary Boundary in J apan-a Discussion ( in Japanese) , Yi7ki3chii. (Foraminifera), no. 11 , pp. 39-46, 1 table. H aynes , J., 1956, Certain Smaller British Paleocene Fora minifera, Pt . 1, Contr. Cushman Found. Foram.. Res., vol. 7, pt. 3, pp. 79-101, pis. 16-18. Hedberg, H. D., and Pyre, A., 1944, Stratigraphy of Northeastern Anzoatequi, Venezuela, Bull.. Amer. Ass. Petrol. Geol., vol. 28, no. 1, pp. 1-28. Hidaka Res.. Group, members of,. 1953,. Problems on the. Mountainland ( in Japanese), Publ. Gecl. Collab. Japan. -30 -. Sedimentary. Rocks in the. Hidaka.

(21) Saburo YOSHIDA Hofker, J., 1956,. Foraminifera from the Cretaceous of Southern Limburg,. Planktonic Foraminifera of. the. Chalk Tuff of. Maestricht and. Netherlands, XIX,. Environments, Naturhist.. },;laandblad, 45e Jrg., no. 5-6, pp. 51-57, 24 figs. Hofker, ]., 1957, Foraminiferen der Oberkreide von Nordwestdeutschland und Holland, Beih. Geol.. ]b., no. 27, 464 pp., 494 figs. Hofker, ]., 1958, Les foraminiferes du Cretace suporieur de Glons, Ann. Soc. Geol. Belg., vol. 81, pp. 8467-493, pis . 1-8, textfigs. 1-3. Hofker, ]., 19S9a, Les foraminiferes du Cretace superieur du Cotentin, 84e Congr. Soc. sav., pp. 370399, figs. 1-68. Hofker, ]., 1959b,. Foraminifera from the Cretaceous of South Limburg, Netherlands, XXXIX :. Arguments for a Lower Paleocene Age of the Sediment above the Upper Md in the Quany of Curfs, near Houthem, Naturhist. Maandblad, 48e Jrg., no. 1-2, pp. 18-30, figs. 1-5. llofker, ]., 1959c, Ditto, XXXX : The Age of the Cr 4, Craie Tuffoide, ibid., 48e Jrg., no. 3-4, pp. 46-50, 2 figs., 1 list. Hofker,. J.. 1959d, Ditto, XLI : The Danian Age of the Maestrichtian Chalk Tuff proved by the. Orthogenesis of Gavelinopsis involuta (Reuss), ibid., 48e Jrg., no. 3-4, pp, 51-53. Hofl<er, ]., 1959e, Ditto, XLIII : Globigerines and Related Forams in the Cretaceous and Lower Paleocene of South Limburg, ibid., 48e Jrg., nos. 7-8, pp. 89-95, 9 figs. llo&er, ]., 1960a, Ditto, XLVII : Buliminae of the Maestrichtian Tuff Chalk, ibid., 49e Jrg., no. 1- 2, pp. 15-19, 15 figs. Hofker. J., 196Gb, Ditto, XLIX : On Another Foraminifera from the Maestrichtian Tuff Chalk Showing Evidence of Danian Age of that Sediments, ibid., 49e ]rg., no. 5-6, pp. 58-60, 6 figs. Hofker, ]., 1960c, The Type Localities of the Maestrichtian (Maestrichtian Chalk Tuff) and of the Montian (Tuffea u de Ciply, Calcaire de Mons, Lagunar, and Lacustre Montian),]. Pal., vol. 34, no. 3, pp. 584-588, 1 text-fig. Hofker, ]., 1960d, Planktonic Foraminifera in the Danian of Denmark, Contr. Cushman Fouud.. Foram. Res., vol. II, pt. 3, pp. 73-86, Text-figs. 1-38, tables 1-6. Hokkaido Coal Min. Techno!., Geol. Section, 1953, Several Problems on the Poronai Formation- a Discussion (in Japanese), Stud. Coal Geol., no. 4, 11 pp., 8 text-figs. Iizuka, Y., 1920, Geological Report on the Kushiro Coal Field, Eastern Part of Kushiro Province (in Japanese), Rep. Min. Res., no. 31. Imai, H., 1924-1925, Stratigraphical and Geologica l Studies of the Tertiary Coal-bearing Formation of the Ishikari Coal Field (The lshikari Series)(in Japanese) , ]. Geogr. Soc. Toky o, vol. 36, pp. 133-157, 253-275, 328-348, 419-427, 519-527, 617- 657, 702-724; vol. 37, pp. 31-44. Imai, H., 1925, Correlation of the Geologic Formations in the Ishikari and the. Kushiro. Coal. Fields (in Japanese), Bull. Coal Min. Ass. Hokkaido, nos. 125-126, pp. 1-19, 9-17. Irnanishi, S., 1952, Neogene Tertiary Deposits in the Akan Area, Kushiro Province, Hokkaido (Abstract) ( in Ja panese),]. Geol. Soc. japan, vol. 58, p. 296. Imanishi, S., 1953, Geology of the Akan Area, Kus hiro Province, Hokkaid<> ( in Japanese) , Contr.. Inst. Geol. Pal., T ohoku Uni'V., no. 44. Israelsky, M. C., 1931. Foraminifera of the Lodo Formation, Central California, Prof. Pap. U. S.. Geol. Surv., no. 240- A, pp. 1-29. pis. 2-11. Israelsky, M. C., 1955, Ditto, ibid., no. 240-B, pp. 31-79, pis. 12-19. -31 -.

(22) The Cretaceous-Tertiary Boundary in Eastern Hokkaidii, }apart Jimbo, K., 1890, An Unexpected Discovery of Mesozoic Fossi ls in Eastern Hokkaidii (in Japanese),. ]. Ceog1·. Soc. Tokyo, va l. 2, p. 590. Kadokura, M., 1918a, Geological Report on the Kushiro Coal Field, Kushiro Province (in Japanese),. Rep. Min. Res., no. 25, pp. 1-84. Kadokura, !VI., 1918b, Geological Report on the Akan Coal Field , Kushiro Province (in japanese) ,. ibid. , no. 27, pp. 1-64. Kawai , M., 19.J6a, Geology of Upper Cretaceous Deposits in the Western Part of Akkeshi Bay, Kushiro Province, Hokkaidii (in Japanese), K oki-chttseikai no Keukyli ( Late NleS('Z . Res.), no. 3, pp. 21- 23, 1 table. Kawai. M., 1936b, Explanatory T e xt of the Geological Map of japan, 1 : 50,CCO, Kombumori Sheet (in Japanese with English Abstract), Geo l. Surv. Japan, 67 pp., 16 pis., 27 text-figs., 16 tables, 1 map. Kobayashi, G., 1914 , Geological Report on the lJrahoro Coa l Field, Kushiro Province (in Japanese) ,. Rep. Min . Res ., no. 18, pp. 1-39. LeRoy, L. W., 1953, Biostratigraphy of the Maqfi Section, Egypt, /vfem . Ceol.. ~vc .. Amer., no. 54,. pp. 1-37, pis. 1-10, figs. 1-4 . Loeblich, A . R., Jr., and Tappan, H., 1957a, Planktonic Foraminifera of Paleocene and Early Eocene Age from the Gulf and Atlantic Coastal Plains, Bull. U.S. Nat. Mus., no. 215, pp. 173-193, text-figs. 27-28, pis. 40-64. Loeblich, A. K, Jr., and Tappan, H., 1937b, Correlation of the Gulf and Atlantic Coastal Pla in Paleocene and Lower Eocene Formations by Means of Planktonic Foraminifera, f. Pal., vol. 31, no. 6, pp. 1109-1137, 5 text-figs . Mallory, V. S., 1959, L ower Tertiary Biostratigraphy of the California Coast Ranges, Pub/. Amer.. Ass. P etrol. Ceo!., 416 pp., 42 pls. Matsui, M., Katsui, Y., Furuhata, Y., and Fuiie, T., 1952, Geology of the Tertiary Formations of the Yubetsu Dis trict, Kushiro Coal Field (in Japanese with English Abstract), f. Cevl. Soc.. japan, val. 58, no. 682, pp. 296-297. Matsui, M., Fuiie, T., and Mitani, K., 1933, Geology of the Takinoue Area, Shiranuka County, Kushiro Province- -a Preliminary Report (Abstract) (in japanese) , ibid., val 59, no. 694, p. 317. Mats ui, M., Furuhata, Y., and Fuiie, T ., 1953, Geology of the Yubetsu Area, Kushiro Coal Field (in Japanese), Pt. I, Chishitsu Y ohO (Bull. Ceal. Comm. Hokkaido ) , no. 22, pp. 1- 29, 5text-tigs., 3 tables, I chart, I map ; Pt. II, Shinseidai no Kenkyil (The. Ceno~.. Res.), no. 17, pp. 7-13, 3 text-. figs. Matsumoto, T .. 19W-19il, On the Urakaw a Transgression in Japan, Jubilee Publ. Commem . Prof. H.. Yahe's 60th Birthday, Pt. II, pp. 743-749. Matsumoto, T., 19! 2-1943, Fundamentals in the Cretaceous Stratigrphy of Japan, Pts. I, JI and Ill,. Mem. Fac . Sci. Kyfishzi Imp. Univ., Ser. D, Vol. L no. 3, pp. 129-280, pis. 5-20 ; vol. 2, no. 1, pp. 97-237, 18 tables. Matsumoto, T., (Editor ). 1953, The Cretaceous System in the Japanese Islands, f ap . Soc. Prom. Sci. Res., T okyo, 338 pp., 36 pis., 77 text-figs.. Matsumoto , T., 1956, ,Fossil-zones of lJpper Cretaceous System and Its World- wide Correlati on ( Abstract) (in Japanese) .. f. Ceal. Sue. japan, vo l. 62, no. 730,. p. 366.. Matsumoto, T., 1939a, Some Problems of th e Cretaceous-Tertiary Boundary with Special Re ferences -32 -.

(23) Saburo YOSHIDA to the World-wide Correlation (Abstract) ( in Japanese) , ibid., vol. 65, no.766, p. 426. Matsumoto, T., 1959b, Ditto, YD.kochft (Fo raminifera), no. 10, pp. 1-17, 2 tables. Mcgugan, A., 1957, Upper Cretaceous Foraminifera from Northern Ireland. ] . Pal., vol. 31, no. 2, pp. 329-348, pis. 31-35, 4 text-figs. McLean, J. D .. Jr., 1951, Paleocene Fora minifera from the Atlantic Coastal Plain, Contr. Cushman. Found. Foram. Res., vol. 2, pt. 1, pp. 20-29, pl. 4. Miller, H. W ., Jr., 1956, Paleocene and Eocene, and Cretaceous-Paleocene Boundary in New Je rsey,. B ull. Amer. Ass. Petrol. Geol., vol. 40, no. 4, pp. 722-736. Minato, M., et al., 19.)2, Wann ersheinen die Poronai-Faunen zum erstenmal?, Proc. fap. Ac., vol. 28, no. 7, pp. 355- 358. Minato, M., Matsui, M., and Ishii, J., 1957, On the Stratigraphi cal Position of the Desmostylus-tooth found in Tokachi (in Japanese with English Abstract), ]. Geol. Soc. japan, vol. 63, no. 740, pp. 308- 316, 2 text-figs., 2 tables. Mitani,. K., 1958 , Upper Cretaceo us Stratigraphy of Eastern Hokkaido and Ils Igneous Activities. (in Japanese), Koki-chilseikai no Kenkyu (Late Mesoz. Res.), no. 7, pp. 37-39. Mitani, K.. and Fujie, T., 1953 ,. On the Tertiary Formation5 of the Takinoue Area, Shiranuka. County, Kushiro Province, Pt. 3 ( in Japanese) , Chishitsu Yoh6 (Bull. Geal. Comm. Hoklzaido), no. 27, pp. 13-28, 4 text-figs., 2 tables. Mitani, K., Fuiiwara, T., and Hasegawa, K., 1958,. Explanatory Text of the Geological Map of. Japan, Scale 1 : 50,000, Nemuro-na mbu Sheet (in japanese with English Abstract), Geol. Surv. Hokkaido, 40 pp., 31 pis., 3 text-figs., 5 tables, 1 map. Mitani. K., Osanai, K., and Hashimoto. W., 1958, Ditto, Ashoro·buto Sheet (in j apanese with Eng lish Abstract). Hokkaid<• Devel. Agency, 66 pp., 18 pls., 5 text- figs., 2 tables, 1. map.. Mitani, K., Hashimoto, W., Yoshida, T., and Oda. Y., 1959, Ditto, Hombetsu Sheet ( in Japanese with English Abstract), Hokkaido Devel. Agency, 83 pp., 21 pis., 15 text-figs., 3 tables, 1 map. Mizuno, A., and Hyakkoku, H., 1960, Ditto, Yubetsu Sheet ( in Japanese with English Abstract), Hokkaidu Devel. Agency, 85 pp., 20 pis., 26 text-fi gs., 9 tables, 1 map. Montanaro, G. E., 1957, A Revision of the F ora minife ra l Family Heterohelicidae, Bull. U. S. Nat.. Mus., no. 215, pp. 133-154, pls. 31- 34. Moore, R. C., 1940, Carboniferous-Permian Boundary, Bull. Amer. Ass. Petrol. Geol., vol. 24, no, 2, pp. 282-336, 3 text-figs. Nagao,. ~S.,. 1957a, Cretaceous Deposits of Hokka ido (The Nemuro Group) (in Japanese), Kiikl-. chilseikai no Kenkyii (Late J)l/esoz. Res.), no. 5, pp. 43-46, 1 table. Nagao, S., 1957b, Mesozoic Deposits of the Akkeshi Area, Kushi ro Province, Hokkaido ( in Japanese),. ibid., no. 6 , pp. 3-7, 1 table. Nagao, S., 1957c, The Mesozoic Group in Easte rn Hokkaidu (The Nemuro Group) ( in Japanese) (Abstract),. f. Geol. Soc. Japan, vol. 63, no. 742, p. 414 .. Nagao, T., 1932a, Some Cretaceous M ollusca from Japanese Saghalin and Hokkaidu (Lamell. and Gastrop.),. f. Fac. Sci., H ok!wdo Imp. Umv., 4th Ser., vol. 2, pp. 23-50.. Nagao, T., 1932b, Two Tertiary a nd One Cretaceous Crustacea from Hokkaido, Japan, ibid., pp. 15-22. Nagao, T., 1941, On Some Fo~sil Crustacea from Japan , ibid., vol. 6, no. 2, pp. 85-100, pl. 26. Nagao, T., and Matsumoto, T., 1938-1939 , A Monograph of the Cretaceous Inoceramus of Japan,. ibid., vol. 4, nos. 3-4, pp. 241-299, pls. 23-34. -. 33.

(24) The Cretaceous-Tertiary Boundary in Eastern Hokkaidi'i, Japan Nagao, T ., 1940, Ditto, ibid., vol. 6, no. 1. Nagao, T ., and Jnoue, T., 1941, Myarian Fossils from the Cenozoic Deposits of Hokkaido and Karafuto, ibid., vol. 6, no. 2, pp. 143-158. Nakkady, S. E., 1955, The Stratigraphic Implication of the Accelerated Tempo of Evolution in the Mesozoic-Cenozoic Transition of Egypt, ]. Pal., voL 29, pp. 702-706. Nakkady, S. E., 1957,. Biostratigraphy and Inter-regional Correlation of the Upper Senonian and. Lower Paleocene of Egypl, ibid., vol. 31, no. 2, pp. 428-447, text-figs. 1-3. Nakkady, S. E., 1958, Stratigraphic and Petroleum Geology of Egypt, Publ. Univ. Assiut, Monogr. Ser., no. 1, PP- 1-215, 37 text-figs., 2 maps. Nakkady, S. E., and Osman, A., 1954, The Genus Globot1'Uttcmw in Egypt, Taxonomy and Stratigraphical Value, 19th Intern. Geol. Congr., Alger, vol. of Abstr., 119. Nishida, S., 1936,. Ceology of the Urahoro Coal Field, Tokachi Province (in Japanese), ]. ]ap.. Ass. Petiol. Techno!., val. 4, no. 1, pp. 37-41. Nishida, S., and Minato, M., 1950,. Shinseidai. 1w. Some Fossils from the Island of Daikokujima (in Japanese),. Kenkyii. (The Cenoi!. Res.) , no. 3, p. 17.. Oda, Y., Nemoto, T., and Uemura, T ., 1959, Explanatory Text of the Geological Map of japan, Scale 1: 50,000, Tokomuro Sheet (in Japanese with English Abstract), Hokkaid<> Devel. Agency, 54 pp., 9 pls., 18 text-figs., 8 tables, 1 map. Oishi, S., and Fujioka, K., 1941a, Studies on the Cenozoic Plants of Hokkaido, Pt. 1 : Ferrns from the Woodwardia Sandstone of Hokkaidii, f. Fac. Sci., Hokkaido Imp. Univ., 4th Ser., vol. 6, no. 2, pp. 177-192, pis. 39-43. Oishi, S.. and Fujioka, K., 1941b, On the Stratigraphical Position of Tertiary Fossil Plants Bearing Formations of Hokkaido and Karafuto (Sakhalin) (in Japanese), ]. Ceo/. Soc. japan, val. 48, no. 573, pp. 298-299. Oishi, S., and Fujioka, K., 1942,. New Species of Woodwardia and Metasequoia from the Harutori. Bed, Kushiro Coal Field, Hokkaidi'i (in Japanese), ibid., vol. 49, no. 587, pp. 172-321, pl. 13. ()ishi, S., and Fujioka, K. 1943a,. Studies on the Cenozoic Plants of Hokkaido and Karafuto. (Sakhalin), Pt. 5 : Tertiary Acers from Hokkaidii and Karafuto, J_ Fac. Sci. Hokkaidi5 Irnp.. Univ ., 4th Ser., vol. 7, no. 1, pp. 82-101, pis. 9-14. Oishi, S., and Fujioka. K., 1943b, ·Ditto, Pt. 6 : On the Tertiary Platanus from Hokkaid<> and Karafuto, ibid., val. 7, no. 1, PP- 103-115, pis. 15- 20. Okazaki, Y., and Yokohira, H., 1958a, Geology of the Cretaceous Deposits on the. Border of. Kushiro and Tokachi Provinces (in japanese), Koki- chtlseikai no Kenkyu (Late Mesoz. Res.), no. 7, pp. 31-32, 1 table. Okazaki, Y., and Yokohira, H., 1958b, Explanatory Text of the Geological Map of Kushiro City and Adjacent Areas, Scale I : 50,000. and 1 : 10,000, Mun. Off. Kushiro, 25 pp., 16 text-figs., 5. tables. Olsson, R. K., 1950, Fo1·aminifera of Latest Cretaceous and Earliest Tertiary Age in Lhe New Jersey Coastal Plain,]. Pal., vol. 34, no. 1, pp. 1-58, pis. 1-12. Otalsume, K., 1943, A Brief Note on Fossil Corbiculids from the Kushiro Coal Field in Hokkaidi'i,. ]. CeDI. Soc. japan, vol. 50, no. 594, pp. 98-100, 1 pl. Oyama, K., Mizuno, A., and Sakamoto. T., 1960,. Illustrated Handbook of Japanese Paleogene. Molluscs, Pub/_ Ceo/. Surv. Japan , 244 pp., 71 pls., 3 text - figs., 7 tables. -. 34 -.

(25) Saburo YOSHIDA Plummer, H. J., 1926, Foraminifera of the Midway Formation of Texas, Univ. Texas Bull., no. 2644, 206 pp., 15 pis. Rao, L. R., 1953, The Problem of the "Danian"--a Review, Current Sci., pp. 359-362. Rao, L. R., 1940, Recent Advances in Our Knowledge of the Upper Cretaceous and Lower Eocene Beds of India, with Special Reference to the Cretaceous-Eocene Boundary, Publ. Dev. Geol.,. Univ. Mysore, pp. 1-44. Reiss, Z., 1952, On the Upper Cretaceous and Lower Tertiary Microfaunas of Israel, Bull. Res.. Cunc. Israel, vol. 2, no. 1, pp. 36-50, 1 table. Reiss, Z., 1955a, Micropaleontology and the Cretaceous-Tertiary Boundary in Israel, ibid., vol. 5B, no. 1, pp. 105-120, 1 table. Reiss, Z., 1955b, Remarks on the Age of Some Late Cretaceous and Early Teritary Stratigraphic Units of Israel, ibid., vol. 5B, no. 1, pp. 121-126, 1 table. Reiss, Z., 1957, Stratigraphic Distribution of Some Mesozoic and Cainozoic Foraminifera from Israel (Notes on Foraminifera from Lsrael, no. 6), Geol. Surv. Israel, pp. 1-5, 1 chart. Renz, H. H., 1951, Remarks on the Age of the Lizard Springs Formation of Trinidad, B. W. !.,. Contr. Cushm,an Found. Foram. Res., vol. 2, pt. 1, pp. 15-16. Said, R., and Abbas, K., 1956, Upper Cretaceous and Lower Tertiary Foraminifera from Northern Sinai, Egypt, Micropaleontology, vol. 2, pp. 105-173, pis. 1-7. Saito, R., 1953, On the Correlation of Paleogene Formations of Hokkaidf> and Kyushu (in Japanese),. Chishitsu Y6ho (Bull. Geol. Comm. Jiokkaido), no. 23, pp. 1-14, 6 text-figs., 5 tables. Saito, R., J955a, On the Correlation of Paleogene Formations of Hokkaido, Kyushu and Formosa (in Japanese),. f. Ass. Kyiishil Min., vol. 23, no. 1, pp. 9-14.. Saito, R., 1955b, On the Correlation of Paleogene Formations in Some Coal Fields of Japan (in Japanese), ibid., vol. 23, no. 6, pp. 215-220. Siato, R., 1955c, On the Poronai Formation, Pt. 1 & 2 (in Japanese), Chishitsu YoM (Bull. Geol.. Comm. !Iokkaid6), nos. 28 & 29, pp. 11-16, 1 text-fig., 1 table, pp. 1-6, 1 text-fig., 2 tables. Saito, K, 1956, Pre-Kishima Orogenic Phase of Ishikari Coal field, Hokkaido (in Japanese),. f. Ass.. Kyilshil Min., vol. 24, no. 5. Saito, R., 1958, The Poronai Group, the Paleogene Formation of Hokkaido (in Japanese), Kumamoto. f.. Sci., Ser. B, Sec. 1, vol. 3, no. 1.. Sasa, Y., 1932, Geology of the Island of Shikotan, the South Kurile Islands-a Preliminary Report (in Japanese), f. Geol. Soc . Tokyo, vol. 39, no. 465, pp. 345-349. Sasa, Y., 1933, A Preliminary Note on the Geology of the Island of Shikotan. Southern Chishima (South Kurile Islands). Proc. 5th Pan-Pacific Sci. Congr. Canada, pp. 2479-2482. Sasa, Y., 1940a, Tertiary Stratigraphy of the Kushiro Coal Field and Some Previous Views of It (Geological Studies of the Kushiro Coal Fields, No. 4) (in Japanese), Bull. Coal Min. Ass.. Hokkaido, nos. 307 & 308, pp. 1-19, 2 tables, 1-24. Sasa, Y., 1940b, Geology and Geomorphology of the Island of Shikotan (in Japanese), Mem. Attic.. lVfus., no. 47. Sasa, Y., 1941, Distribution of Coal-bearing Formations of the Kushiro Coal Field-a Preliminary Report (Geologic! Studies of the Kushiro Coal Fields, No. 5) (in Japanese), Bull. Coal JV!in. Ass.. Hokkaido, nos. 319-321, pp. 1-16, 15-28, 1·8. Sasa, Y., 19.12, Existence of Coal-bearing Formations Beneath the Kushiro Plain (in Japanese), -35-.

(26) The Cretaceous-Tertiary Boundary in Eastern Hokkaido, Japan. ]. Hokkaido Min. Ass., vol. 1, no. 10. Sasa, Y., 1950-1951, On the Coal Fields of Hokkaido, Pt. 1 & 2 (Commentary) (in Japanese),. Chishitsu Yoho (Bull. Geol. Comm. Hokkaido), nos. 15 & 17, pp. 13-21, 13-19, 2 tables. Sasa, Y., 1951, Review of Geological Papers Recently Published (in Japanese), Tanka Gijutsu. (Hokkaido Coal Min. Techno!.), vol. 6, no. 5, pp. 29-30. Sasa, Y., 1953, Geological Problems on the Kushiro Coal Field ( in Japanese), f. Geol Soc. japan, vol. 59, no. 694, p. 347. Sasa, Y., 1956a, Several Problems Concerning the Paleogene Tertiary of Hokkaido (in Japanese),. Yl1kochfi (Foraminifera), no. 6, pp. 1-22, 5 text-figs., 2 tables. Sasa, Y., 1956b, On the Geology of the Island of Shikotan (in Japanese), Koki-chuseikai no Kenkyu. (Late Metoz. Res.), no. 3, pp. 23-25, 1 table. Sasa, Y., 1957, On the Geology of the Island of Shikotan (in Japanese) , Chishitsu. Yohi5 (Bull.. Geol. Comm. Hokkaidii), no. 34, pp. 28-29, 1 table. Sasa, Y., and Nishida, S., 1933, Synthetic Stratigraphy of the Cenozoic Formations of South-eastern Hokkaido-a Preliminary Report (in Japanese) , j. Geal. Soc. japan, vol. 42, no. 501, pp. 349-350. Sasa, Y., et al., 1951, Several Problems on the Geology of the Kushiro Coal Field (in Japanese),. Tanka Gijutsu (Hokkaido Coal Min. Techno!.), vol. 6, no. 8, p. 29. Sasa, Y., and Hayashi, L, 1952 , Stratigraphy of the Cretaceous System and the Type of Pre-Tertiary Diastrophism in the Eastern Part of the Kushiro Coal Field (in Japanese), j. Geol. Soc. japan, vol. 58, p. 292. Sasa, Y., Nemoto, T., Hashimoto, W., and Matsuzawa, T., 1952, Explanatory Text of the Geological Map of Hokkaid<\ Scale 1 : 600,000 ( in Japanese) , Hokkaido League Aclv. Sci. Techno!. Stanley, D. ]., 1960, Stratigraphy and Foraminifera of Lower Tertiary Vidono Shale, near Puerto Ia Cruz. Venezuela, Bull. Amer. Ass. Petrol. Geol., vol. 44, no. 5, pp. 616- 627, 2 figs., 2 tables. Suzuki, ]., 1958, Problems Concernig the Geology of Hokkaidl, (Special Address) ( in Japanese) , j.. Geol. Soc. japan, vol. 64, no. 759, pp. 663-674, 1 text-fig., 1 table. Suzuki, K., 1944,. Notes on Some Tertiary Non-marine Molluscs from North Nippon ( in Japanese),. ibid., vol. 51, no. 606, pp. 100-109, 2 pis. Suzuki, Tatsuo, 1923,Discovery of Ammonites from the Kushiro Coal Field, Hokkaid() (ip. Japanese), ]. G. Soc.Toky<J, vol. 30, p. 97; j. Geogr. Soc. Tokyo , vol. 35, p . 115. Suzuki, Tatsuo, 1925, Report on the Itoizawa Coal Producting Place, Kushiro Province (in Japanse),. ]. Geogr. Soc. Tokyo, vol. 37. pp. 59- 60. Suzuki, Tatsuo, 1930a. Ditto, Rep. jlfin. Res., no. 37, pp. 35-43. Suzuki, Tatsuo, 1930b, Report on the Arekinai Coal Producting Place,. Kushiro Province. (in. Japanese), ibid., no. 37, pp. 25-34. Suzuki, Taisuke, 1958, Explanatory Text of the Geological Map of Japan, Scale 1 : 50,000. Shiranuka Sheet ( in Japanese with English Abstract) , Hokkaidu Devel. Agency, 46 pp., 8 pis., 11 text-figs., 7 tables, 1 map. Takahashi, K., 1959, On the Unconformity Existing Between the Yasukawa Group and the Upper Yezo Group, Abeshinai River Area, Teshio Province, Hokkaidii (in Japanese with English Abstract), ]. Geol. Soc. japan, vol. 65, no. 768, pp. 537-544, 6. text~figs ... 1 table.. Takayanag, Y., 1957, Review of the Recent Studies on the Upper Cretaceous Foraminifera, especially on Globotruncana and Its Allies (in Japanese), Yllkochii ( Foraminifera), no. 7, pp. 41-60, 7 text-36 -.

(27) Saburo YOSHIDA fi gs., 2 t ables. Takayanagi, Y. , 1959a, The Cretaceous-Tertiary Boundary from th e Veiw P oint of Studies of the Smaller Foraminifera ( in japanese), ibid., no. 10, pp. 18-29 , 3 ta bles. Takayanagi, Y. , 1959b, Ditto (Abstract) ( in Japanese), ]. Geot. Soc. j apan, vol. 65, no. 766, p. 423. Takayanagi, Y. , 1960a,. Annotated Bibliography of the Cretaceous Foraminifera fr om Japan ,. Sci.. Rep. T 6hoku Univ. , 2nd Ser., Spec. Vol., no. 4 ( Prof. S. Han zawa Mem. Vol.) , pp. 309-315 . Takayanagi, Y., 1960b, Review of Hofker's "Foraminifera from the Cretaceous of Southern Li mburg, Netherland" ( in Ja panese), Kaseki ( Fossil) , no. 1, pp. 87-101, 7 tables. Takayanagi, Y., 1960c, Cretaceo us Foraminifera from Hokkaido, Japan, Sci. Rep. T ohoku Univ., 2nd Ser., vol. 32, no. 1, 154 pp., 11 pis., 22 text- fi gs., 11 tables. Takeda, H., 1953, The Porona i Forma tion (Oligocene Tertiary) of Hokkaido and South Sakf.alin and Its Fossil Fauna, Stud. Coal. GeJl., no. 3, 103 pp., 13 pis., 18 text-figs., 5 tables. Takeda, H., and Hashimoto, W., 1949, New Consid eration on the Cretaceous Formation in Hok kaido ( in Japa nese with English Abstract) ,. f. j ap. Ass. Petrol. Techno{., vol. 14, no . 4 , pp. 146-153,. I table. Tanai, T., 1957, Exp lanatory Text of the Geological Map of Japan, 1: 50,000, Ombe tsu Sheet (in Japanese with English Abstract) , Hokkaido Devel. Agency, 52 pp., 10 pls., 8 text- figs., 8 tables. Tappan, H., 1960, Cretaceous Biostra tig raphy of Northern Alaska, Bull. Amer. A ss. Petrol. Geol., vol. 44, no. 5 , pp. 615-627, 2 fi gs., 2 tables. Tokuda , S., 1929,. Several T opographical and Geological Problems on Karafuto ( Sakha lin) (in. Japanese), f. Geogr. Soc. T okyo , vol. 41, no. 486, pp. 453- 45 7. Tokunaga, S., 1960, Review of Kopp's "Inocera men im Tertiiir des Mittelmeerranumes" (in Japanese) ,. f. fap. Ass. Petrol. Techno!., vol. 25, no. 3, p. 130. Troelse n, J. C., 1957, Some Planktonic Foraminifera of the Type Danian and Thei r Stratigraphic Importance, Bull. U. S. Nut. Mus., no. 215, pp. 125-132, text-figs. 22-24 , pl. 30. Tromp, S. W ., 1949, T he Determinati on of the Cretaceous-Eocene Boundary by Means of Qua ntita tive, Generic, M icrofauna \ Determinati ons and the Conception "Danian" in the Near East, ]. Pal., vol. 23, no. G, pp. 673-676. Trulillo, E. F., 1960, Upper Cretaceous Foraminifera fro m Near Redding, Shasta County, California, ibid., vol. 34 , no. 2, pp. 290-346, pls. 43-50.. Uch io,. T ., 1960, Rev iew of. Hofker's "Fm·a minifera from the. Cretaceous of. South. Limburg,. Netherlands" (in Japanese) ,]. Geot. Soc. Japan, vol. 66, no. 777, pp. 426-428. Ujii ~.. H., and Watanabe, H ., 1960, The Porona i Fm-aminifera of the Northern Ishikari Coal Field ,. Hokkaidii, Sci. Rep. Tokyo Kyoiku Daigaku, Sec. C, n o. 63, pp. 117-136 , 3 pis., 4 text-figs., 4 tables. Vershchagin, V. N., 1957, "Fundamental Problems on the Cretaceous System in Far-East" (Translated into Japanese by Z. Konishi), Bull. Geal. Surv. j apan, vol. 9, nos. 3-5, 1958. Watanabe , K., 1915, Geological Report of the Shitakara Area, Shiranuka District, Kushiro Province (in. Japanese), Rep. Min. Res., no. 21, pp . 1-65.. Watanabe, K., 1917, On the Dis tributi on of Cretaceous Forma tions in I-lokkaid<> ( in Japanese) , ].. Geogr. Soc. Tokyo , vol. 29, p_ 417. Weiss, L., 1955a, Planktonic Index Fo ra minifera of Northwestern P e ru, Micropaleaniology, val. 1, no. 4, pp. 301- 319, pis. 1-3, text-fig. 1, tables 1-2, 1 chart.. -37 -.