

A GENERAL GEOGRAPHIC CHANGE. 51 



epicontinental sea from extensive areas within the continent, and in such 

 wise that shallows and archipelagos of low flat islands took the place of 

 wide mediterraneans. A similar physical change is indicated for eastern 

 Asia. The physical history of both continental regions was one of pro- 

 longed submergence, favorable to cosmopolitan evolution, which resulted 

 in the development of related faunas in the two areas; and the withdrawal 

 of marine waters checked the faunal variation at the same stage on opposite 

 sides of the globe. The geographic change was not occasioned by notable 

 disturbances of the continental masses, although there probably was some 

 gentle warping; but it may with reason be ascribed to a decided deepening 

 of the ocean basins. The trend of the evidence, which may be traced more 

 in detail in America and Europe than at present in Asia, is to establish 

 proof of a general lowering of the sea-level, such a change as Suess desig- 

 nates a negative eustatic movement.* The world-wide prevalence of the 

 preceding marine transgression, its long duration, the corresponding devel- 

 opment of identical life conditions and consequently of closely related 

 organisms, and the universality of the sea-level datum, all combine to 

 render that particular negative movement one of the most definite time 

 records in geologic history. 



*La Face de la Terre, vol. n, p. 841. 



