QUATERNARY DEPOSITS. 223 



Oriskany falls, being readily recognized from local differences in the rock prevailing at all its 

 points of outcrop. The same rock was also found, but in small blocks, near Skaneateles 

 village, with characters resembling those of its outcrop to the north of that village. 



The limestones of the Helderberg division are far more abundantly distributed south, ovnng 

 to its greater thickness. They may be seen from one end of the district to the other. A few 

 points only will be noticed. In the creek to the east of Cherry- Valley, at a considerable ele- 

 vation above the valley, and therefore far above the outcrop of their parent's bed, are many 

 large blocks, having fallen from above. They are numerous over the south part of Herkimer 

 and Oneida, but more so in Madison county, in the tovras of Eaton and Madison. In the last 

 named town are many lime-kilns, which are supplied by transported blocks. A place was 

 visited, where a large block was buried, except a projecting point, and was supposed to be in 

 place, or in other words, was a limestone ledge. ' They are also in abundance along the waters 

 of Limestone creek in Onondaga county. Nimierous points along the line south of the range 

 of that division show the distribution of the limestone blocks, and the field enclosures are often 

 made of them. Among the kinds the comiferous limestone is very prominent, being easily 

 recognized by its nodules of flint and its fossils. 



The Tully limestone, in large angular masses, has been found as far south as about twelve 

 miles from its present outcrop ; being about the same distance that the blocks of Oriskany 

 sandstone, at the south of West-Hamilton, are from where the rock exists in place at the falls. 

 The most numerous blocks discovered of the Tully limestone were on the west side of the 

 district, near Cayuga inlet. The largest specimen was found on Six-mile creek, on the farm 

 of Mr. Hollister. It was so large a mass, that, being partially buried, it was considered to 

 be in its original position. At both of these localities, the transported blocks are burnt for lime. 

 The highest point noticed where the same rock appear as a boulder, is near the little mill on 

 the road to Dryden, about two miles from Ithaca. 



From the boulders being generally seen resting upon the surface, they have the appearance 

 of having been but recently transported ; and thus favor the opinion so strongly advocated, 

 that whilst the portion of the continent of which they form a part was submerged, they were 

 deposited from icebergs. The following facts show that there is fallacy in those appearances ; 

 and though ice may have been the instrument of their carriage in the first instance, it probably 

 was of more local origin than marine icebergs. All over the district, boulders are rare in the 

 broad valleys, being always more numerous upon the hills, their sides, and the foot of the hills ; 

 appearing to have fallen, or otherwise removed, from the place where they were first let down 

 or deposited. This fact shows that their transportation took place before the valleys obtained 

 their present surface, or their diffusion would be more general ; or else those deposited in the 

 valleys have been carried up to a higher level, a fact yet to be ascertained. 



One of the causes of tlie transportation of boulders or blocks of rock, is the sudden breaking 

 of lake barriers, or other large bodies of water ; these, in New-Hampshire and in the Alps, 

 have been known to effect the carriage of large rocks for miles of distance. Another, and the 

 more general and tranquil agent, is ice, either in the form of bergs, being parts of glaciers, 

 or of the thinner product of lakes and rivers. 



