168 GEOLOGY. 



noted, that the epicontinental sens withdraw unequally in different regions, 

 as for example from the eastern Gulf region earlier than from the Atlantic or 

 the western Gulf coasts. The other phase is expressed in the vertical upbowing 

 of certain tracts, usually old mountain tracts, such as the Appalachian in the 

 present case. In general, those borders of a continent that do not suffer crus- 

 tal shear and folding, are apt to be bowed in this way as a part of the deeper 

 deformation of the continental segment, resulting from its squeezing between 

 the adjoining oceanic segments, as heretofore explained. 



The deformations at the close of the Cretaceous seem to have been of the 

 typical earth-body type, expressing themselves in all the characteristic phases — 

 basin sinking, sea withdrawal, crustal shear, folding and faulting, vertical bowing, 

 and general warping. 



Igneous eruptions. — The close of the Cretaceous was attended by 

 exceptional igneous activity, the eruptions beginning late in the Laramie 

 epoch. It was during this period of igneous activity that many of 

 the great bodies of igneous rocks of the west, whether extrusive or 

 intrusive, were forced up. Fig. 406 shows the relation of igneous intru- 

 sions to Cretaceous beds in the Crazy mountains of Montana. It may 

 be noted in passing, that igneous eruptions occurred in other lands 

 at the same or about the same time, among them the lava-flows of 

 India, the greatest on record. 



Upper Cretaceous of other Continents. 



Europe. — As shown by the distribution of the Upper Cretaceous 

 strata of Europe, extensive transgressions of the sea occurred at the 

 beginning of this period. What is now the central plateau of France 

 was land during the Earlier Cretaceous (Comanchean) period, but was 

 largely submerged during the Later. So also was much of the great 

 land area of the Earlier Cretaceous period lying northeast of the Paris 

 basin. In Saxony, Silesia, and Bohemia, the Upper Cretaceous sys- 

 tem is widespread, and rests on Paleozoic strata, indicating, or at 

 least suggesting, that the submergence was more general for this 

 region than in any earlier period of the Mesozoic. During the closing 

 stages of the Upper Cretaceous, fresh-water beds appear in localities 

 (Alpine region) where marine sedimentation had been in progress, 

 showing that the region was by this time affected by the movements 

 which were to mark the close of the era. 



Russia was more extensively under water during the Earlier Cre- 

 taceous period than most other parts of Europe, but even here the 



