358 



M. YOKOYAMA. 



name oï I zumi- Sandstone^ from tlie prédominance of a certain greenish- 

 grey liard sandstone, locally kn(5wn under the name of Izumi-stone. 



Fossils from this sandstone are very few. l>esides a laro*e so- 

 called Fucoid which occurs at several places in Sanuki, we know only 

 a Hdicoccras described below, and some fragments of a large Haiuitea- 

 like Ammonite found by ^Ir. Suzuki at Okuzure in Awaji. Harada,'^ 

 however, mentions also some F(^raminifer:i, bivahes, and conifers as 

 occurring in this sandstone. 



The Mesozoic Basin of the Kalsuragawd occu])ies tlie upper part of 

 the ri\er of the same name in Awa. Tt wns freoloofically inves- 

 tigated in 1883 by Mr. Y. Kikufhi, to wliom we owe tlie first dis- 

 covery of the Cretaceous formation in Shikoku. Here it consists of 

 sandstones and conglomerates, superposing tlie Jurassic plaiit-bearing 

 series. The sandstone is hard, tine-UTained, and when fresh oTeenish- 

 grey in coLnu', and has nearly the same appeai'ance as the Tzumi-stone, 

 while on weathering it assumes a vellowish tint. It contains shells in 

 great profusion, wliich hmvever belong to a very few species, aud are 

 mostly found as casts. They are — 



Trigonia jwciUifonnis, 

 Trifjonia Kikueliiana, 

 Trigonia rot undo fa . 



Mr. Kikuclii also found a fragment of an evoliite as well as of 

 a spirally rolled Ammonite. 



The Monohegawa Basin is in Tosn. Its geological nnture is not 

 well known. We possess only a block of sandstone like that of tlie 

 Katsuragawa, (piite filled with casts of Trigonia pocilliforriiis. 



The Bgöschi Basin is not far from the above, and occupies the 

 southern portion of Xagaoka-gori, Tosa. Here the Cretaeecnis forma- 



1) Loc, cit., p. 107. 



