CEPHALOPODA FKOM THE HOKKAIDO. O 



also wrote on the Cretaceous fauna of tlie island, giving an 

 account of 47 species, of which 2 had ah'eady been described by 

 YoKOYAMA and 6 are considered as identical with those of South 

 India and other foreign localities, while 28 species are treated as 

 quite new. 



The Cretaceous formation in the main island of the Hokkaido 

 occupies a position between the coal-bearing series above and the 

 Palaeozoic rocks'^ below, stretching generally north-south along 

 the western side of the main axis of the island. It consists of 

 deposits of a purely marine origin, with a rich fauna mostly made up 

 of numerous Cephalopoda, Gasteropoda and Lamellibranchiata, and 

 sometimes containing some vegetable remains. Among these three 

 groups of the jNIollusca, the Cephalopoda are the most abundant, 

 both in species and individuals. Besides the Mollusca, we find some 

 Brachiopoda, Echinodermata, Crustacea and sometimes also fishes;"^ 

 vertebras of Reptilia, apparently of a Plesiosaurus, were also once 

 obtained. 



Concerning the age of the Cretaceous deposits of the Hokkaido, 

 various opinions have been held since the publication of the two 

 works above referred to. Yokoyama, who only investigated fossils 

 collected by others, naturally expressed a doubt as to whether 

 all the fossils came from a single horizon, and cautiously said 

 that the greater part of tlie fossils corresponded to those of the 

 Utatur group of South India and consequently that they should 

 . be assigned to the Cenoman-Gault of Europe. Jimbö on the 

 contrary, considered the Ci-etaceous fossils of the Hokkaido as 

 occurring in one and the same horizon of the middle Cretaceous 



1) xVfter JiMB>) ami ilie general us:ige of Japanese geologists. 



2) H. Yabe: Notes on s )nie Shark's Teeth from the Mesozoic Formation of Japan. 

 Journ. Geol. Sue. Tokyo. Vol. IX. No. 110. l'JU2. 



