GEOLOGY OF THE VICINITY OP LITTLE PALLS O 



rocks has brought out the facts here given and the detailed evi- 

 dence will be presented later. 



Sketch of physical changes. The rocks of the Adirondack region 

 are among the oldest of which we have knowledge anywhere on 

 the earth's surface. The history Avhich they disclose is an exceed- 

 ingly difficult one to decipher and has been only imperfectly made 

 out as jet. It is however clear that it involves the passage of a 

 prodigious lapse of time. 



The oldest known rocks of the Adirondack region are of the sort 

 deposited from water, and indicate that the region, probably in its 

 entirety, was below sea level and receiving deposit on its sur- 

 face. These deposits would seem to have been of the same, or very 

 similar, sort as those now being deposited on shallow sea floors : 

 sands, muds, calcareous muds and their intermediate gradations. 

 These rocks were apparently deposited in great thickness, though 

 we have no means at present of ascertaining what that thickness 

 was. They must have accumulated on a floor of older rocks, but 

 this older floor has not yet been certainly made out in the Adiron- 

 dack region. It may or may not be present. Volcanic action 

 seems to have been going on while these deposits were forming, or 

 else occurred not long afterward. 



After these conditions had persisted for a long time, the dis- 

 trict was raised up out of the water, probably to considerable 

 hight, accompanied by a certain amount of folding, fracturing and 

 tilting of the rocks. The surface ceased to receive deposit, and 

 instead was attacked by the weather, the surface deposits were 

 disintegrated and decayed, this loosened material commenced to 

 move down hill toward the sea, and the surface was thus pared 

 away bit by bit and lowered. This action continued through long 

 ages till many hundred, likely a few thousand, feet of rock had 

 been thus patiently removed. 



The region also was early the scene of vigorous igneous action. 

 Whether this preceded, accompanied and perhaps caused, or fol- 

 lowed its uplifting above sea level is not known; but enormous 

 masses of molten rock invaded the region from beneath in a great 

 series of intrusions. Whether anv of this material ever reached 



