i\){) Ni:\V VUUK ST ATI-: MUSEUM 



Chapter 9 



LARGER GLACIAL LAKES OF THE CnAMPLAIN AND 

 HUDSON VALLEYS (continued) 



LAKE VERMONT OR GLACIAL LAKE CHAMPLAIN 



From the failure of the lii<»lior sliore lines of the Lake Chaui- 

 I)lain district to pass around the northern spur of the Adirondacks 

 at Covey hill and thus westward along the northern Hank of the 

 mountains it seems as before stated necessary to postulate an ice 

 dam across the mouth of the Champlain valley acting as a barrier 

 to retain the waters in it up to these higher levels. The waters 

 thus confined in the Champlain valley already recognized by Bald- 

 win, Ui)ham and others, have been referred to as glacial Lake 

 Champlain. As this body of water was of far greater extent 

 than Lake Champlain and came into existence independently^ of 

 this smaller lake and moreover was separated in time from Lake 

 Champlain by a marine episode in the valley, it seems best to 

 employ a distinctive name. As the glacial lake covered practi- 

 cally much of the state of Vermont west of the Green mountains 

 and probably penetrated through that range at its highest stages 

 to the basins on the east of the mounta-ins, " Lake Vermont '' is 

 used here instead of the descrijitive phrase heretofore employed. 



This body of water was apparently at first as noted by Upham 

 confluent on the south with what is in this paper denominated 

 Lake Albany. Just how far north in the Cham])lain valley the 

 ice had retreated at this early stage depends on the interpreta- 

 tion of the higher gravel ridges and boachlike deposits in the 

 northern half of the Champlain valley. On the extent to which 

 the ice had retreated de])cnds in turn the extent at any time of 

 the lake toward the north. The outlet of these ice-dammed waters 

 at this early stage of confluence across the present divide of the 

 Hudson and Chamj)lain basins is a matter which concerns the 

 interpretation of Lake Albany on the south and is considered in 

 thai connection. Lake Vermont may be said proj)erly to have 

 come into existence when in consequence^ of a local lowering of 

 the wafers south of Fort Edward a discharge began across a bar- 

 lier inio Ihe Hudson vallev on the south. 



