188 DISCUSSION OF THE DESICCATION QUESTION. 



common observation that in cold latitudes floods terminate ordinary snowy 

 winters. The subsidence of northern lands would have brought on the 

 conditions of a warmer climate; and, as the melting went slowly forward, 

 this amelioration must finally have become very decided. Consequently, 

 there Avas melting, not merely along the southern edge of the glacier, but 

 over its wide surface ; and, when the thickness of the ice was at last reduced 

 to a few hundreds of feet, and it had become rotten throughout, the meltina; 

 must have gone forward with greatly augmented rapidity; and a flood, fill- 

 ing rivers and lakes to an unwonted height, must inevitably have followed. 

 The fact that such a flood, vast beyond conception, was the final event in 

 the history of the glacier is apparent in the peculiar stratification of the 



flood-made deposits Only under the rapid accumulation of immense 



amounts of sand and of gi-avel and of water from so unlimited a source, could 

 such deposits have been accumulated." 



Professor Dana is so profoundly impressed with the importance as a geolo- 

 gical event of the melting of the " great glacier," that he makes of the time 

 of its occurrence a distinct period in the Quaternary age, to which he gives 

 the name of " Champlain," dividing this period into two epochs, the Dilu- 

 vian, and the Alluvian. According to him, the earlier part of the Champlain 

 period " was the era of the melting of the great glacier, and of most local 

 glaciers; and therefore the era of immense floods along the valleys; of many 

 and great lakes ; and of the deposition of the sand and gravel of the glacier.'"* 

 This early portion of the Champlain period constituted the"Diluvian epoch." 

 The "Alluvian epoch," on the other hand, formed " that part of the era of 

 depression, after the melting had ended, characterized by depositions of a 

 more quiet character." 



As it will be necessary-, farther on, to refer again to these views of Professor 

 Dana's, it is sufficient, at present, to point out that there is, in his Manual, 

 no special reference to any cause of diminution of water-surface, on the 

 globe, other than that implied in the above quotations, except in so far as 

 reference is had to the building up of the continental masses, or the gain of 

 the land upon the sea. The prominent facts with regard to the desiccation 

 of large portions of the American and Asiatic continents, where no "great 

 glacier" ever existed, have not been noticed by him. 



On examining the works of European geologists, it is found that the idea 

 of a moister climate as connected with the Glacial epoch, and a deluge of 



* 1. c, p. 543. 



