Hayasaka — Richthofenia in Japan. 465 



Aet. XXXIX. — On the Occurrence of Richthofenia in 

 Japan; by Ichiro Hayasaka. 



The eastern, or Pacific half of the northernmost part 

 of the main Island of Japan, the area between the strait 

 of Tsngaru and the Bay of Sendai, is called Kitakami 

 monntainland. The southern part of this plateau-like 

 land has for a very long time been known to yield many 

 interesting and important fossils of Paleozoic as well as 

 of Mesozoic ages. The famous locality of Triassic 

 ammonites, described first by Mojsisovics and later by 

 Diener, called Inai, is situated in the southernmost part 

 of the monntainland ; Pseudomonotis occurs at several 

 localities a little north of Inai. Many other animal 

 fossils, as well as land-plants, are found a little further 

 north. 



These Mesozoic formations rest unconformably upon 

 the abraded surface of a complex of black clay slate, 

 with sandy clay slate and limestone, that together com- 

 pose the younger Paleozoic system of the region under 

 consideration. The Paleozoic rocks also are at certain 

 places very rich in fossils, and several of the latter have 

 been described by Yabe and by myself. 



The Paleozoic of southern Kitakami yields, besides a 

 few species of Fusulina, several forms of brachiopods 

 and corals. Of the former, Lyttonia was described by 

 Yabe 1 in 1900, and more recently by myself 2 in 1917. 

 In addition, I have described several other species of 

 brachiopods, and the paper is now ready for publication. 

 Yabe and myself 3 have described several- species of corals, 

 and a part of this has been published in a preliminary 

 form. Another species worthy of notice is Amblysiphon- 

 ella*, which was formally recorded as Steinmannia by 

 Yabe. 5 



In general, brachiopods are associated with Fusulina, 

 but corals do not occur with either of them as a rule, 



1 Yabe : The Brachiopod Lyttonia, etc., Jour. Geol. Soc. Tokyo, No. 79. 



2 Hayasaka : On the Brachiopod Genus Lyttonia, etc., Ibid., No. 288. 



3 Palaeozoic Corals from Japan, etc., Ibid., vol. 22. 



4 Hayasaka : Amblysiplwnella from Japan and China, Sci. Eep. Tohoku 

 Imp. Univ., vol. 5, No. 1, 1918. 



5 Yabe : Materials for a Knowledge of the Anthrac. Fauna of Japan, 

 Jour. Geol. Soc. Tokyo, No. 104, 1902. 



