THE COMANCHEAN PERIOD. 129 



In southern Europe the marine sedimentation of the preceding 

 period was not interrupted, and the Lower Cretaceous beds rest con- 

 formably, and with poor definition, on the Jurassic. Limestone is 

 here the most common sort of rock. In southeastern Europe, Lower 

 Cretaceous beds are found in the southeastern part of Russia (Cauca- 

 sus, Transcaucasia and Transcaspian regions) and about Moscow. 



Other continents.— Lower Cretaceous formations of marine origin 

 are widespread in Siberia, Japan, 1 and southern Asia, but in limited 

 areas only in most other parts of tne continent. The system is believed 

 to have slight development in the mountain regions of northwestern 

 Africa, where it is really a continuation of the Lower Cretaceous of 

 southern Europe, and is unconformable beneath the Upper Cretaceous, 

 and in South Africa. 2 Marine Lower Cretaceous is also widespread 

 in the northern part of South America, but not elsewhere east of the 

 Andes. The absence of marine Lower Cretaceous beds east of the 

 Andes in the southern part of South America is in keeping with its gen- 

 eral absence about the borders of the South Atlantic generally. On 

 the other hand, marine Lower Cretaceous beds occur in many places 

 about the southern Pacific and Indian Oceans, 3 as in India, the Hima- 

 layan region, Australia, New Zealand, and at a few points on the east 

 coast of Africa, and perhaps elsewhere. The areas where the system is 

 exposed are, however, mostly small. 



Climate. — In the aggregate, the known fossils of the Lower Cre- 

 taceous of America are not such as to indicate great diversity of climate. 

 Even in Greenland, the climate seems to have not only been milder 

 than now, but as warm as that of warm temperate regions of to-day. 



While the climate of the Cretaceous periods has not been deter- 

 mined in detail, European fossils seem to afford better evidence of the 

 existence of zones than those of America. From them paleontologists 

 have thought to find warrant for the hypothesis that the climate under- 

 went more or less fluctuation during the course of the periods. 



The fresh-water fossils of those deposits of central Europe which 

 represent the transition from the Jurassic to the Lower Cretaceous, are, 



1 Outlines of Geology of Japan, 1902, pp. 59-73. 



2 Ann. Rept. Geol. Com. Cape of Good Hope, 1901, p. 38: and Corstorphine, His- 

 tory of Stratigraphical Investigations in South Africa, Rept. S. Af. Assn. for Adv. 

 of Sci., 1904. Geology of Cape Colony, Rogers, 1905, pp. 281-330. 



3 Neumayr. Erdegeschichte, Bd. II. 



