REPORT OF THE DIRECTOR I912 87 



ceased and the whole southern Adirondack region was raised above 

 sea level and underwent erosion. The western portion of this land 

 area was of Precambric rock while the surface rock in the eastern 

 portion was Little Falls dolomite. 



To summarize for the Cambric period : All evidence is decid- 

 edly against a complete submergence of the southern Adirondack 

 region during the late Cambric period, the land mass of the time 

 having occupied at least all of Hamilton county except its south- 

 eastern portion ; all the northern half of Herkimer county ; and 

 most of the eastern portion of Lewis county. This axis of ele- 

 vation most likely continued northeastwardly through the Adi- 

 rondack region to its northeastern portion and occupied about the 

 same area as the present main axis of elevation of the mountains. 

 The close of the Cambric witnessed an uplift sufficient to convert 

 the wdiole southern Adirondack region into dry land. 



ORDOVICIC PHYSIOGRAPHY 



Early Ordovicic. According to Ulrich and Cushing^^ the 

 Tribes Hill limestone is the earliest Ordovicic formation. Its 

 distribution demonstrates that the Mohawk valley to a little 

 northwest of Little Falls and the lower Black river valley were 

 submerged. Its total absence from the southwestern Precambric 

 boundary, from the outlier at Wells, and from the vicinity of 

 Northville and Saratoga Springs strongly suggests that little if 

 any of the southern Adirondack region was submerged under the 

 Tribes Hill sea. This limestone is probably not present in the 

 Champlain valley but, if it is, a little of the eastern border of the 

 Adirondacks may have been submerged. It would seem, there- 

 fore, that this Tribes Hill submergence was not as extensive as 

 that of Little Falls time. After the deposition of the Tribes Hill 

 limestone, however, there was a long erosion interval continuing 

 to Black River time and hence because of removal of Tribes Hill 

 limestone by this erosion it is more than likely that the present 

 outcrops do not indicate the full extent of the Tribes Hill sea. 

 At any rate there is not the slightest direct evidence for any con- 

 siderable submergence of the southern Adirondack area at this 

 time. 



During the long interval between Tribes Hill and Black River 

 times the w^hole southern Adirondack region was above sea level 

 except locally along the western border for a short time when 



^■6 Pages 128-30. 



