l6 NEW YORK STATE MUSEUM 



has been too much reference of static water features of unknown 

 relationship to " glacial " without proving the fact. The writer 

 can not be charged with any prejudice against glacial lakes; but he 

 has named no lake without knowing its control. 



ABSENCE OF MARINE LIFE IN THE HUDSON VALLEY 



No well-attested marine fossils have been found in the Hudson 

 valley, or in the higher water-laid deposits of the Champlain valley. 

 Partly for this reason the appeal has been made to glacial waters. 



The tides are felt in the Hudson " river " to Albany, but brackish 

 water reaches only to about Poughkeepsie, and salt water organisms 

 pass up the Hudson only to the Highlands. The problem relating 

 to the Pleistocene waters becomes simply the exclusion of salt 

 water. 



When the receding ice front was slowly giving place to the deep 

 estuarine water in the Hudson valley these were loaded with silt^ 

 for the land drainage was gathering in the freshly laid mantle of 

 drift and the melting glacier was contributing its load of rock flour. 

 The thick clay beds resting on the till or glaciated rock are suffi- 

 cient evidence. The waters were cold and muddy, and unfavorable 

 to nearly all forms of marine life. 



Another deterrent factor was the volume of fresh water. The 

 ablation of the glacier probably supplied, even in the lower Hud- 

 son, sufficient fresh water to exclude the salt-water fauna. And 

 when the ice front receded to Albany the flood from the Ontario 

 basin swept into the Hudson, and for long ages subsequent all the 

 drainage now represented by the St Lawrence, plus the water from 

 the melting of the ice sheet for a thousand miles on the west, were 

 forced south through the narrow passes at Whitehall, West Point 

 and the Palisades. And during this stage the wave uplift of the 

 glaciated territory had probably lifted the lower Hudson valley to 

 nearly its present height. Such uplifted condition is indicated in 

 the maps, plates i and 2. 



When the ice front reached Covey hill the outdrainage of the 

 Laurentian basin was merely shifted from the Mohawk pass to the 

 Covey pass, and the cold, fresh waters still passed south. When 

 the ice front recession let Lake Iroquois fall and blend into the 

 sea-level waters, so that the latter occupied the Ontario basin (see 

 plates 2, 3, 5), the ultimate outlet was the same. And this south- 

 ward flow through the Hudson of all the glacial waters, and the 

 land drainage, from Duluth to Maine, persisted until the waning of 



