QUATERNARY DEPOSITS. 221 



is, friction in the form of rubbing and collision, occasioned by the movement of the boulder 

 itself ; and the second, alteration from exposure to the weather, which, commencing with the 

 angles and edges, finally leaves the mass in a globuliform state, should its nature admit of 

 alteration or decomposition. In North and South Carohna, where granite of a readily alterable 

 character exists, rounded masses of the kind are in many parts extremely numerous ; they 

 have, however, undergone no change of place, but merely a concentric decomposition in place. 

 Boulders, with some exceptions, are found over the whole of the district exclusive of its 

 southern border, where they were not noticed, but yet may exist. The whole of them, with- 

 out an exception south of the Helderberg range, have been transported from north to south, 

 or rather from a northern position. The greater number consist of primary rock, which have 

 been carried a much greater distance than any of the others ; and as a general rule, the farther 

 they were seen to the south, the smaller was their size. The distribution of the boulders is 

 yery unequal, very numerous in some places, and but few in others. With some exceptions, 

 they are generally found upon the surface, frequently upon the tops of hills or on their sides ; 

 appearing in almost all their localities as if but recently dropped, and that no change had 

 taken place subsequent to that transportation which brought them from their original position. 



Boulders of Primary Rock. 



The most southern part of the district where boulders of primary rock were noticed, was 

 in the valley which leads from Vanettensville to Spencer in Tioga county ; they were of the 

 smaller size, and composed of granite. They are not remembered to have been seen south 

 of two miles below the village of Cortland. In Shed's ravine, south of Truxton, there is 

 quite a large one, being from four to five feet in diameter. North of the village, and in the 

 neighborhood, there are a number, but of a smaller size, all likewise of primary rock. They 

 occur also near Preble. 



Boulders of the same kind are yet more numerous in the valley at the head of Otisco lake, 

 on the road to Homer. A few appear near SpaflTord, towards the ridge, between the road and 

 the lake ; also on both sides of Skaneateles lake. 



Through Madison county, they are seen in numerous places on the hills and hill-sides, 

 extending into Chenango county. One of the largest seen in this county is in the village of 

 Peterboro' ; it consists chiefly of white quartz, with a little white feldspar and garnet : it was 

 the largest seen south of the Mohawk. 



Boulders are very numerous at the north end of Otsego county, being found on all its hills. 

 They occur in profusion on the limestone terrace to the northeast of Cherry- Valley village, and 

 the enclosures there are principally formed of them. They appear in many of the creeks in 

 the valley, having fallen from a higher level. In the same situation, also, they are seen in 

 many parts of Oneida county south of the Mohawk, as in the ravine back of Dr. Noyes's near 

 Hamilton college ; in Bridgewater valley, etc. etc. 



