REPORT OF THE DIRECTOR AND STATU GEOLOGIST 



part of the readjustments of the region have been effected in this 

 way, since many slight slips may involve as great an amount of 

 shift as that concentrated along a single great fault. 



Pleistocene deposits 



. The retreating and disappearing ice sheet of the glacial period 

 dropped its burden of transported rock material very unequally; 

 much at points which mark pauses in the retreat; far less over 

 places away from which the retreat was rapid; much also in the 

 depressions of the preglacial surface, filling them often to the 

 brim. In the district immediately under consideration glacial 

 deposit, morainic and of till, is widespread but of very unequal 

 thickness and with much bare rock showing. In places are very 

 considerable morainic accumulations. The old preglacial valleys 

 cut in the high plain level are refilled to that level, while the old 

 hill tops and divides are but scantly covered. 



Moraines. Much the most considerable line of morainic de- 

 posit is that banked up against the southeast face of Rand hill, 

 climbing up and overtopping it to the south and swinging to the 

 west up the north side of the £aranac valley, deeply covering all 

 rock over a great area, and not improbably hiding the preglacial 

 ►Saranac valley as well. The moraine is quite sandy, as is true of 

 all moraines hereabouts, in consequence of the large content of 

 material derived from the Potsdam sandstone. It is also very 

 stony, and again material of Potsdam source is much the most 

 conspicuous element. Locally the surface is exceedingly stony. 

 Potsdam boulders by the hundred lying about together with 

 crystalline rocks from Rand hill and rare Calciferous and 

 Canadian pre-Cambrian blocks. This is undoubtedly the oioraine 

 mentioned by P>aldwin in his paper on the Pleistocene of the 

 Champlain valley. 1 This moraine, which covers all the south 

 face of Rand hill and the low hills westward, as well as the south 

 slopes of Dannemora mountain, so that all rock is hid and the 

 pre-Cambrian-Potsdam contact efficiently concealed, would seem 

 an unmistakable terminal moraine. 



American geologist. 1S94. 13:S94. 



