PALAEONTOLOGICAL SOCIETY OF JAPAN SPECIAL PAPERS NUMBER 10 LATE TERTIARY FLORAS FROM NORTHEASTERN HOKKAIDO, JAPAN By Toshimasa TANAI and Nobuo SUZUKI PUBLISHED BY THE SOCIETY February 20, 1965 President: Kiyoshi ASANO Councillors: Kiyoshi ASANO (Editor of "Fossils ,,), Haruyoshi FUJIMOTO, Tetsuro HANAI (Editor of Transactions and Proceedings), Wataru HASHIMOTO (Treasurer), Kotora HATAI, Ichiro HAYASAKA, Koichiro IcHIKAWA, Teiichi KOBAYASHI, Tatsuro MATSU­ MOTO (Editor for Special Papers), Masao MINATO, Hiroshi OZAKI (Planning), Tokio SIll KAMA (Membership), Fuyuji TAKAI (Chairman of Executive Councillors' Committee), Taro KANAYA, Ryuzo TORIYAMA Assistant Secretary: Takeo ICHIKAWA All Communications relating to this Journal should be addressed to the PALAEONTOLOGICAL SOCIETY OF JAPAN c/o Geological Institute, Faculty of Science, University of Tokyo, Japan Special Papers, Palaeontological Society of Japan Number 1 (Issued September 25, 1951) Bibliography of Japanese Palaeontology and Related Sciences, 1941-1950 ............... · ............................................................... Compiled by Riuji ENDo Number 2 (Issued March 1, 1954) Matajiro YOKOYAMA'S the Pliocene and Later Faunas from the Kwanto Region ....... ............................................ Revised by Isao TAKI and Katsura OYAMA Number 3 (Issued August 31, 1957) Matajiro YOKOYAMA'S Tertiary Fossils from Various Localities in Japan. Part 1 ..... ............................................................. Revised by Jir6 MAKIYAMA Number 4 (Issued June 30, 1958) Matajiro YOKOYAMA'S Tertiary Fossils from Various Localities in Japan. Part 2 ..... ............................................................. Revised by Jir6 MAKlYAMA Number 5 (Issued December 15, 1959) Matajiro YOKOYAMA'S Tertiary Fossils from Various Localities in Japan. Part 3 ..... · ............................................................. Revised by Jir6 MAKlY AMA Number 6 (Issued July 25, 1960) Matajiro YOKOYAMA'S Tertiary Fossils from Variou:;; Localities in Japan. Part 4 ..... · ............................................................. Revised by Jir6 MAKlYAMA Number 7 (Issued November 30, 1961) Japanese Permian Bryozoa ............................................ Sumio SAKAGAMl Number 8 (Issued September 20, 1962) Tertiary Marine Mollusca from the Joban Coal-Field, Japan ........ Yasuhiko KAl>lADA Number 9 (Issued December 15, 1962) Bibliography of Japanese Palaeontology and Related Sciences, 1951-1960 ............... ............................................................. Compiled by Fuyuji TAKAl Special Publications, Palaeontological Society of Japan Twenty-Fifth Anniversary Volume (Issued February 15, 1961) Catalogue of Type-Specimens of Fossils in Japan ..................................... ................... Compiled by Shoshiro HANzAwA, Kiyoshi ASANo and Fuyuji TAKAl Twenty-Fifth Anniversal Volume (Issed September 16, 1963) A Survey of the Fossils from Japan Illustrated in Classical Monographs (Primarily A Nomenclatorial Revision) ............................ Edited by Tatsuro MATSUMOTO Available from the University of Tokyo Press, University of Tokyo, Hongo, Tokyo. LATE TERTIARY FLORAS FROM NORTHEASTERN HOKKAIDO, JAPAN By Toshimasa T ANAl Department of Geology and Mineralogy, Faculty of Science, Hokkaido University and Nobuo SUZUKI Geological Institute, Kushiro Branch, Hokkaido Gakugei University CONTENTS PART 1. SYSTEMATICS By Toshimasa T ANAl and Nobuo SUZUKI Page Introduction .............................................................................. 1 Acknowledgements. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 2 Systematic Descriptions ........................................................ , .. .. .. .. .. 2 A Summary of Systematic Revisions. .. 48 PART II. COMPOSITION AND INTERPRETATION By Toshimasa T ANAl Present Physical Setting .................................................................. 51 Physical Conditions ....... " .............. " .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... 51 Woody Vegetation .................................................................... 51 The Shanabuchi Flora .................................................................... 52 Introduction .......................................................................... 52- Geologic Occurrence .................................................................. 54 Composition .......................................................................... 55 Jii Systematic List of Families and Species ............................ , . .. .. .. .. 55 Assumed Growth Habit. ................................................... ········ 57 Numerical Representation ........................................................ 58 Paleoecology .......................................................................... 59 Distributional Considerations ...................................................... 61 The Elements of the Shanabuchi Flora........................................ 62 The East Asian Element 67 The Central and Northern Honshu Component ........................ 67 The Central China Upland Component .. , ............... , .. .. .. .. .. ... 72 North American Relationships ............................................ 75 The Shanabuchi Plant Associations................................................ 76 Climate............................................................................ 82 'The Rubeshibe Flora. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... 84 Introduction .......................................................................... 84 Geologic Occurrence .................................................................. 85 Systematic List of Families and Species ............ , .. .. .. .. .. .. .. .. .. .. .. .. .. ... 86 Assumed Growth Habit............................................................ 88 Numerical Representation.......................................................... 90 Paleoecology .......................................................................... 94 Distributional Considerations ...................................................... 94 The East Asian Element............................. .. .. .. .. .. .. .. .. .. .. 94 North American Relationships ................................................ 96 Comparison of the Rubeshibe and Shanabuchi Percentage Representation. .. ... 97 The Rubeshibe Plant Associations ................................................ 98 Climate ............................................................................ 100 'Other Late Tertiary Floras of Northeastern Hokkaido ...................... , ............. 100 The Samakesaroma Flora ................................ , .. " ......................... 100 The Ikutawara Flora .................................................................. 102 'Correlation and Age ...................................................................... 102 Stratigraphic Evidence ................................................................ 103 Evidence of Floral Composition ........................................................ 108 Summary ................................................ , ............................. 111 'Conclusion ................................................................................ 111 Bibliography .............................................................................. 113 Index of Fossil Names Plates Tables 'Table 1 Climatic Data for Abashiri . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... 52 2 Assumed Growth Habit of the Shanabachi Plants ................................ 59 3 Numerical Representation of Shanabuchi Species. .. .. .. .. .. .. .... .. .. .. .. .. .. .. ... 60 4 Present-Day Distribution of the Shanabuchi Genera .............................. 63 5 Modern Equivalents of the Shanabuchi Plants and their Distribution in Eastern Asia and North America .......................................................... 64 6 Slope Plants of Honshu and Shanabuchi Equivalents.............................. 68 iii '7 Plants of the Mixed and Subapline Forests of Central and Northern Honshu, and Shanabuchi Equivalents............................................................ 71 8 Living Equivalents in the Uplands of Central China..... .. .. .. .... .. .. .. .. .. .. ... 73 9 Eastern North American Plants and Shanabuchi Equivalents. .. .. .. .. .. .. .. .. .. ... 74 10 Climatic Data for Several Localities in Japan, China and the United States. .. ... 83 11 Assumed Growth Habit of the Rubeshibe Plants. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... 88 12 Numerical Representation of Rubeshibe Species .................................. 89 13 Present-day Distribution of the Rubeshibe Genera. .. .. .. .. .. .. .. .. .. .. .... .. .. ... 91 14 Modern Equivalents of the Rubeshibe Plants and their Distribution in Eastern Asia and North America .......................................................... 92 15 Percentage Representation of Species Common to the Rubeshibe and Shanabuchi Floras ............................................................................ 97 16 Occurrence of Shanabuchi and Rubeshibe Plants in Other Neogene Floras of Japan .. 104 17 Percentage of Element Representation in Neogene Floras of Japan ................ 110 Figures Wigure 1 Localities of Late Tertiary Plants in Northeastern Hokkaido. .. .. .. .. .. .. .. .. .. ... 53 2 Location of Principal Neogene Floras