JOURNAL OK THE COLLEGE OF SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN, 



VOL. XIX., ARTICLE 20. 



Jurassic Ammonites from Echizen and Nagato. 



By 



Matajiro Yokoyama, Rigakuhakushi. 

 Professor of Palaeontology in the Imperial University of Tokyo. 



With 4 plates. 



A. Ammonites from Echizen. 



The occurrence of Ammonites in the Jurassic plant-bearing 

 scries of the province of Echizen was known as early as 1882, 

 when Dr. Kochibe discovered them in a shale near the village 

 of Shimoyama in the same province. No collection of them, 

 however, was made, until Mr. M. Matsusiiima, after a careful 

 search near Kaizara and its vicinity in 1885 succeeded in finding 

 several specimens which were afterwards deposited in the museum 

 of the Science College of the Tokyo University. The results of 

 the study of these fossils are as follows. 



According to Mr. Matsushima, the rock-layers exposed along 

 the river Ishidoshiro, a branch of the Anamegawa in the district 

 of Ono, consist of a basal conglomerate and a complex of shales 

 and sandstones. This complex is divided by him into three parts, 

 the Lower or Ammonite-bed, the Middle or Plant-bed and the 

 Vppev or Gyrena-bed. It is in this Ammonite-bed that the above 

 fossils were found. The chief locality for them is Horadani near 



