Lutiieh — Economic Geology of Onondaga County. 



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500 to 800 feet above the bottom of the valley. The intervale is an alluvia] 

 plain having an average descent toward the north of twelve feet to the mile. 

 Unlike the other four valleys that have been excavated through the Helder- 

 berg escarpment in this county, the Onondaga valley becomes wider after it 

 readies the hard limestones in the vicinity of the Indian reservation, about 

 midway betw een the head and Onondaga lake, spreading out into a plain one 

 and one-half to two and one-half miles wide. The sides of the valley decrease 

 somewhat in height, but are still 250 t<> 400 feet high, steep and rocky, 

 abounding in cliffs and ledges, the location of man)' quarries. The ridge on 

 the east side of the valley extends to Ley creek, a little north of the head of 

 Onondaga lake, with a deep valley crossing it, tw o miles from the north end, 

 through w hich the Erie canal and the New York Central railroad find passage 

 to the eastward into the city of Syracuse. On the opposite side the hills recede 

 toward the west, and do not reach quite so far north. The basin of Onondaga 

 lake is located in the low section of the county, extending in a northwesterly 

 direction from the line of the Helderberg escarpment. It is excavated to the 

 depth <>f 450 to 500 feet in the Salina red shales, and is a continuation of the 

 old channel, which is now the vallev of Onondaga creek. The bottom of this 

 channel at the head of the lake has been found to be fifty-two feet below the 

 level of the sea. At the Solway Co.'s first w ell at Tully, the drill penetrated 

 400 feet of sand and clay without reaching the rock, and in two wells on the 

 east side of the valley, forty-five feet of drift was found in one, and in the 

 other, 590 feet therefrom toward the center of the valley, 322 feet. The 

 latter well is about 2,000 feet from the center of the valley. Nowhere in the 

 middle of the valley is bed rock exposed, nor has it been reached by drilling, 

 and there is every probability that the great depth of the old channel below 

 the bottom of the present valley, found at both the head and the foot of this 

 lake, is continuous throughout its w hole length. 



The Otisco lake valley has its beginning in Cortland county, and extends 

 in a northwesterly direction. From the foot of Otisco lake southward it is 

 about half a mile wide, with steep sides, where the soft shales are frequently 

 exposed. The hills adjacent to this part of the valley rise from 800 to 1,000 

 feet above the bottom of the valley. The valley is narrower north of the 

 lake, and the outlet, known as Nine Mile creek, runs among drift hills and 

 shale knolls to Marcellus village, where a narrow rocky canyon begins, w hich 

 is cut through the Helderberg escarpment to the depth of 250 feet, about four 

 miles to Marcellus station. From this point Nine Mile creek Hows tow aid the 

 northeast through a narrow valley haying steep sides and a flat alluvial inter- 



