558 



CENOZOIC TIME. 



4. Exterminations by the Cold Waters. — While the reen forced Lab- 

 rador current of the Diluvian era drove Arctic and Subarctic marine 

 species southward along the northern coasts, the ice and ice-cold 

 waters of rivers carried destruction to the life of more southern seas. 

 Professor Hilgard states that the Orange sand or stratified Drift of 

 the Mississippi valley, where it enters the Mexican Gulf, contains no 

 traces of marine fossils, and for the reason that the great ice-cold 

 stream was like a Labrador current let loose in the Tropics. The 

 estuary and shore deposits about New Haven, Connecticut, are equally 

 destitute of marine shells, and for the good reason that Long Island 

 Sound was actually occupied with ice, whether the land were more 

 elevated than now or not. 



B. Champlain Period in Foreign Countries. 



The Glacial period of Britain and Europe was followed, as in 

 America, by an era (the Champlain) in which the land stood below 

 its present level, and extensive beds of stratified Drift, overlaid and 

 somewhat interstratified by others of more quiet deposition, were 

 made along sea-borders, lake-borders, and river valleys. The sea- 

 border formations of Sweden and Norway are closely like those of 

 the coasts of Maine and the St. Lawrence, even to the " Leda clays " 

 and " Saxicava sands" And the valleys of Europe, especially over 

 its northern half, have their extensive river-border formations, which 

 are equivalents of those along the American river-valleys. 



Lyell states that the facts lead to the inference that, after the period 

 of elevation with which the Glacial era began, there " succeeded a 

 period of depression and partial submergence," and of accumulations 

 of sand and bowlder-clay, with peaty clay in a few places. This de- 

 pression in Great Britain varied in different parts from 1,300 to 500 

 feet, except over southern England, where it may have been only 100 

 or 200 feet. In Sweden, the depression varied from 200 feet in the 

 south to 400 or 500 in the north ; and Erdmann proves that the Bal- 

 tic was connected with the North Sea, over the region of lakes from 

 Stockholm westward, and with the Arctic ocean by a great channel 

 leading northeastward over Finland to the White Sea. It is even 

 probable that the Caspian and Aral Lakes at this time communicated 

 with the Northern Ocean. 



The facts from Europe confirm the conclusion from America, that 

 the Champlain period was the era of flooded rivers and lakes, and of 

 the most extensive fresh-water formations in the world's history. Du- 

 pont states that with the close of the floods the flood-grounds of the 

 river Meuse, near Dinant in Belgium, were diminished in breadth from 

 seven and a half miles to a fourth of a mile ; and this is an example 

 of the general change over Europe. Europe also had rivers dammed 



