THE CRETACEOUS PERIOD 757 



which were to mark the close of the era were making themselves felt. 



Limestone is the dominant sort of rock in the Upper Crustaceous 

 of southern Europe, showing that clear seas still prevailed, as in the 

 Early Cretaceous period. From a characteristic genus of fossils, 

 much of the limestone is known as Hippurite limestone. In the 

 system farther north, there is more clastic material. 



The most notable petrographic feature of the Upper Cretaceous 

 of Europe is the chalk. Both in England and France it attains an 

 aggregate thickness of several hundred feet, though much of it is 

 far from pure. It grades into marls and clays on the one hand, 

 and into sandstone on the other. Chalk is, however, by no means 

 coextensive with the system, for it has little development outside 

 of the Anglo-French area. The name " Cretaceous/' therefore, as 

 generally used, is as inappropriate as a name could well be, having 

 no applicability to the Lower Cretaceous, and fitting only a rela- 

 tively small area of the Upper. Even within the areas where chalk 

 occurs, it is not everywhere the dominant sort of rock. Greensand 

 occurs in the Upper Cretaceous as well as in the Lower. The prin- 

 cipal subdivisions of the system recognized in western Europe are 

 1. Albian; 2. Cenomanian; 3. Turonian; 4. Senonian, and 5. 

 Danian, numbered from the base up. 



Asia. The submergence of Europe and North America at the 

 beginning of the Upper Cretaceous finds its parallel in other conti- 

 nents. There are extensive areas of Hippurite limestone in south- 

 western Asia, closely connected with that of Europe on the one 

 hand, and with that of North Africa on the other. The Himalayan 

 region seems to have been still beneath the sea, for Upper Creta- 

 ceous formations are found in the mountains at great elevations. 

 Greensand occurs in the Salt Range of India. 1 South of these 

 marine beds there appears to have been a large tract of land, in- 

 cluding much of the peninsula of India, which has been thought 

 to have stretched southwest to Africa, though the configuration of 

 the sea-bottom does not lend this view much support. 



Upper Cretaceous beds occur on the eastern coast of China, and 

 in Japan. In many places they rest on formations older than the 

 Lower Cretaceous, and therefore record an increased submergence 



1 Seeley, Geol. Mag., 1902, p. 471. 



