REPORT OF THE DIRECTOR I912 89 



considerably less than forty miles, and this is the most likely view. 

 By a similar line of reasoning Gushing^ has shown that the Trenton 

 sea could not have reached more than ten miles north of the north 

 boundary of the Little Falls quadrangle. The thickness of about 

 three hundred feet of Trenton (mostly shale) in the outlier at Wells 

 shows that the Trenton sea must have reached at least a few miles 

 north and west of that locality. Pebbles of Precambric rock and 

 grains of sand in the Trenton limestone at Wells, however, make 

 the existence of near-by land (Precambric rock) practically a cer- 

 tainty as argued by Kemp."^ 



From the above statements we conclude that dry land existed in 

 the region of southwestern Hamilton county and also most pro- 

 bably over all of northern Hamilton county. It is worthy of note 

 that this Trenton land mass, with northeast-southwest trend, oc- 

 cupied the same region as the present belt of highest land in the 

 southern Adirondacks, and also that this land mass, though now 

 smaller, occupied the same position as that of late Cambric and 

 early Ordovicic times. The absence of Paleozoic rock outliers west 

 of a northeast-southwest line through Wells and North River at 

 least affords interesting negative evidence in harmony with this view. 



Regarding Utica and Postutica times the results of recent work 

 are decidedly against submergence of the whole Adirondack region. 

 Considering the great thickness of Paleozoic strata ; the slope of the 

 surface of the Precambric rock; and the existing altitudes within 

 the Adirondacks, Walcott, Cushing and the writer have all been 

 led to conclude that the late Ordovicic sea must have extended 

 almost, if not quite, across the whole Adirondack area. Many 

 years ago Walcott^^ said : " There was a practically conformable 

 deposit of sediments against and over the area of the Adirondack 

 mountains from early Cambric times to the close of the deposition 

 of the Utica shales, except in the case of the unconformity by non- 

 deposition between the Potsdam and the Chazy." 



Later Cushing,^ as a result of his studies along the northeastern 

 border of the Adirondacks, said : '* The basal Potsdam is found 

 running up to an elevation of seventeen hundred fifty feet in the 

 northern Adirondacks. With the relief of the region as it is now 

 the deposition of the minimum thickness (four thousand feet) of 



1 Page 17. 



2 Page 61. 



7 Page 152. 

 17 Pages 24-25. 



