On some Cretaceous Fossils from Shikoku. 



By 

 Malajiro Yokoyama. 



With Plate XL. 



The Cretaceous F<n-iii:i1i<)n iii Shikoku occurs in several places. 

 These occurrences, however, are re^trictcl to two zones, lying one on 

 each side of, and paridlel to, the central zone of crystalline schists, 

 wliicli traverses tlie island from EXE to W8W along its longitudinal 

 axis. The Cretaceous strata in tlie northern zone directly overlie 

 these schists, and f )rni a long narrow helt along the whole nortliern 

 coast of the island, interrupted only here and there hy alhivial flats. 

 ]>e3^ond Shikoku, they continue on the e:ist over the southern portion 

 of the island of Awaji to the Katsuragi ^[ouiitains in Kii, while on 

 the west, vanishiiig partly uiider the sea arid partly under the voJcanic 

 rocks of Kyfishfi, they seem to reappear on the islands of Amakusa. 

 In the southern zorie, they are not so conti rmous. They rather fill up 

 trough-like depressions in the Palaeozoic rocks, together with some 

 other memhers of the ^lesozoic Grou]). Tliese depressions are known 

 as the Katsnragaim Basin, the MonohiUjuwa Badu^ tlie Bijöschi Basin, 

 and the Sakawa Basin. Ihit here also the zonal distriljution of the 

 Cretaceous rocks is quite evident, as these basins all lie in one straight 

 line parallel to the longitudin;d axis of the island. 



The northern zone is essentially composed of alternatiiig layers of 



sandstone and shale, for whicli complex Dr. lfarad:d' proposed the 



/ 



1) T. ilarada. Die Japanhchen Inseln. — Eine topo(jv(t2)hisi-h.-tjt'oh>(ji^che Uehersiclit. I Lief. 

 Pullislted by the Imperial Geological Survey of Japan, 1890. 



