■8 NEW YORK STATE MUSEUM 



possible drift barrier, like the narrow section oi the Highland, 

 below West Point. And no belt of drift, marking any strong reces- 

 sional moraine, has been recognized in the valley north of the ter- 

 minal moraine. It may be noted that a blockade at the Narrows 

 would be ineffective with the Harlem valley and Long Island sound 

 open. 



For the Champlain valley a possible land barrier is the col or 

 ■divide between Fort Edward and Whitehall. But it has been shown 

 (93, page 10) that the divide is not a river channel, or at least has 

 not carried any stream flow in Postwisconsin time. Moreover the 

 conspicuous terraces built in standing iwater lie, continuous, on 

 both sides of the valley up to 300 feet over the col. Indeed, it is 

 important to note that at any point where any kind of dam can be 

 proposed, in either the Hudson or the Champlain section of the 

 ^reat valley, the evidence of long-standing water will be found 

 immediately below (south of) the dam site at an altitude quite as 

 high as above (north of) the station. 



An idea has been held that some of the shore features, especially 

 for the valleys of New England, were the product of ice-border 

 lakes ; the waters being held in embayments of the valley walls by 

 the lobations of the ice margin. In the Hudson-Champlain valley 

 such lateral pondings would be possible at only a 'few localities, 

 where deep embayments or tributary valleys were limited on the 

 south by bold salients. A steady water level of some duration 

 would require a land outlet, and such should be dicoverable. If 

 the escape of the water was alongside the ice margin, as must 

 nearly always have been the case, the impounded waters would be 

 inconstant in level and ephemeral, and the shore features would be 

 weak and indefinite. Even if recognizable deltas or other inscrip- 

 tions were left by the marginal waters, those of the separate lakes 

 would have no consistent relationship in altitude. The only locali- 

 ties in the great valley where shore phenomena are found that 

 might suggest marginal iwaters are at West Point, Crown Point, 

 Port Henry and at Port Kent and Keeseville. But even granting 

 the efficiency of marginal lakes in a few embayments, this does not 

 explain the fact of strong, practically continuous and consistent 

 shore features the whole length of the valley. Marginal glacial 

 waters are probably a negligible factor in the Hudson-Champlain 

 valley, and for all the New England valleys that declined away 

 from the ice front directly toward the open sea. 



A fair consideration of the factors involved in the valley his- 

 tory, and of the features seen in the field, will rule lake waters out 



