UPLIFTS OF THE MOHA^^Ti. 



209 



The seventh uplift or series, is that of Little-Falls. It presents the same barrier-like 

 appearance, at the east end, as the Noses, with no equivocal character as to origin at all 

 observable ; the valley at both extremities on both sides of the river presenting the slate in its 

 integrity, with, however, a thick shield of alluvion on the north side, at the west or upper end. 

 It is the only one which the river has not succeeded in cutting down to a level at both ends ; 

 probably owing to the great height as well as the breadth of the gneiss which forms its base, ex- 

 tending as it does from the east to the west end, and forming the bed of the river, over which 

 the water falls. The uplift presents a wall on the east side, rising above the range of slate to 

 some height on the north side of the river, and only broken where the river finds its passage. 

 The gneiss rises at the east end to the height of a hundred feet, and disappears under the 

 calciferous rock and the river at the west end. On the north side of the gap, its overlying 

 rock, towards the east end, has been removed, presenting a terrace of many rods in breadth, 

 and showing a greater breadth of river when at that height. On the south side the terrace is 

 but a narrow one. 



An interesting feature in the gap, as regards its antiquity and the progress of excavation, 

 are the pot-holes in the primary rock. They are found at different elevations, some high above 

 the present level of the river. They are numerous in the bed of the river, and occur between 

 the river and the level of the aqueduct ; at the raihroad house ; and in the wall of rock which 

 rises above the road going east, after crossing the bridge. At this latter place, a section of 

 one of them may be seen, extending from the top of the cliff to about fifteen feet below, look- 

 ing like a niche for a statue, but reversed. These holes are obviously due to the rubbing or 

 grinding of stones, put in motion by an obhque movement of waters, where rapids or falls 

 exist. 



The calciferous sandrock forms the whole mass which rises upon the primary on both sides 

 of the Gap, extending north and south as in wood-cut No. 70. In part it rises vertically, 

 showing a thickness of over two hundred feet : it is thicker at the west than at the east end. 

 Its layers appear in the gap to be nearly horizontal, owing to the course of its excavation 

 having been in the line of its bearing, the dip being about southwest. The fucoidal layers 

 were not noticed, except at the old mill in the direction of its slope ; they were but thin. 



Section north and south, passing through lAttle-Falh. 



No. 1. Primaiy rock, gneiss. 

 2. Calciferous sandrock. 



Geol. 3rd Dist. 



No. 5. Utica slate. 



27 



No. 3. Birdseye limestone. 

 4. Trenton limestone. 



