GEOLOGY OF THE NORTH CREEK QUADRANGLE 65 



feature probably even more prominent. The comparatively even sky 

 line of the western Adirondacks together with the high plateau 

 called Tug Hill just west of the Black River valley, practically 

 prove the former peneplain condition of that portion of the 

 Adirondacks. This peneplain is known to have been elevated late 

 in the Cretacic period or the early Tertiary period and, as already 

 stated, much of the faulting of the eastern Adirondacks occurred 

 at the time of th.at great uplift or even later. Thus the fact that 

 this peneplain had considerable irregularities on its surface, com- 

 bined with the facts of excessive tilting of the earth blocks by fault- 

 ing and subsequent erosion, have quite efifectually masked even 

 this later peneplain surface. Doctor Ogilvie says with reference 

 to the Paradox lake quadrangle,^ that the even sky line of some of 

 the mountains suggests an uplifted peneplain, and also that the long, 

 smooth, eastward slopes of the fault blocks probably represent por- 

 tions of the peneplain surface which were produced before the 

 faulting. Similar evidences occur within the North Creek quad- 

 rangle as, for example, the rather even sky lines of the Henderson, 

 Pine-Gage, Huckleberry, and Chase mountain masses, and the 

 numerous eastward-sloping fault blocks already described. Any- 

 thing like accurate knowledge of the character of this Mesozoic 

 peneplain within the map limits is, however, lacking. 



GLACIAL AND POSTGLACIAL GEOLOGY 



CHANGES OF LEVEL 



It is important to recall the well-known fact that the eastern 

 portion of North America, including the Adirondack region, im- 

 mediately preceding and doubtless during a good part of the Glacial 

 epoch was notably higher than it is today. The submerged chan- 

 nels of the lower Hudson and St Lawrence rivers prove that the 

 land there must have been something more than 1000 feet higher 

 than now in order to have allowed the channel cutting. Toward 

 the closing stages of the Ice age, and directly after it, there was 

 a submergence of the whole region to below the present level as 

 shown l)y the so-called raised beaches or delta {lei)osils in the Hud- 

 son and Champlain valleys. In the Champlain vaUey tlie deposits 

 are chiefly clays which were formed in an arm of llic sea as proved 

 1)y the presence of marine fossils, 'lliese deposits are now several 

 liundred feet al)ove sea level in the Champlain valley, which proves 



^ N. Y. State Mus. P.ul. 96, p. 468. 



