6 ART. 2. — H. YABE : CRETACEOUS 



this complex is another which is also thick and consists chiefly 

 of sandstones with subordinate layers of shale and conglomerate. 

 This formation, being a more littoral deposit than the above, 

 is very poor in Cephalopoda while Gasteropoda and Lamelli- 

 branchiata, especially the remains of Trigonia, are common. The 

 writer gives to this series the name of Trigonia-^^u(\s,ionQ. The 

 upper Ammonite-beds, which directly cover the TH^oma-sandstone, 

 are again argillaceous, being mainly composed of shales with a few 

 layers of sandstone. Most of the fossils described by Professors 

 YoKOYAMA and JiMBö and above alluded to, as well as the 

 greater part of my collection, were derived from these beds. 



The fossils described in the following pages are partly those 

 already treated by Jim ho in his work and partly those collected 

 by tlie writer during his field work in the provinces of Ishikari, 

 Teshio, Iburi and Kitami, while some are those belonging to the 

 museum of the Science College. Not a few have been presented 

 to the writer by gentlemen, who have kindly interested themselves 

 in his w^ork. 



The writer begins the present memoir with the description of 

 those groups of Ammonites which have been hitherto included in 

 the genus Lytoeeras, but which are now separated into Lytoceras, 

 Gaudryceras and Tdragomics. A general discussion on the nature 

 of the fauna will be given at the end of the memoir. 



In the present paper, the geographical names of the Hokkaido 

 have been spelled according to Batchelor's^^ system of writing 

 Ainu names, and those of the other parts of Japan according to 

 the system adopted by the Society for romanizing Japanese 

 Writing. These two systems are essentially the same in principle, 



1) Ainu-Englisli-Japanese Dictionary ami Grammar by tlic Kovcrcnd John Batchelor. 

 läöU. 



