NEW YORK. 



73 



find its present rocky channel. Even though the drift rose only a foot higher than the rocks, it would 

 as effectually force the water over the rocks as if it formed a mountain. Could the river have once 

 surmounted the drift, its work would have been comparatively easy in wearing out a bed through 

 the old ravine, but till it was able to flow over the barrier it would have no power over it, and must 

 commence its slow work of wearing away the solid rock. The present gulf shows us what it has 

 done since the drift period. J. HALL AND SIR CHARLES LYELL. 



40. At Black Rock there is only from 6 to 14 inches of the Onondaga limestone which is of a 

 grayish color, crystalline and contains few fossils. The Corniferous limestone above it is 25 to SO 

 feet containing abundance of hornstone. It is dark colored, fine grained, and in its fresh fracture, 

 and particularly when wet, it presents an almost black appearance, which has given the name of 

 Black Rock to the place. It affords good quarries of excellent building stone. From the occurrence 

 of the Corniferous along the south end of Lake Erie and its dip southward, it seems probable that 

 the bed of this lake has never been excavated below it, and that it now forms the floor beneath the 

 deposit of alluvium. It seems that there are others of the lake bottoms composed of limestone, 

 especially Lake Ontario. See note 71. This is probably for the reason that it received a polish from 

 the action of glaciers which then passed over it, while the resistance of the grit of the sandstones 

 and shales was more favorable for deeper excavation. Lake Erie is 230 miles long, 50 miles wide, 

 140 feet deep, and and its surface is 569 feet above tide. 



41. Batavia is the highest point on the N. Y. C. & H. R. R. R., and one of the highest in Western 

 New York, being 887 feet above tide. This is caused by there crossing the 9 c. Helderberg form- 

 ation, which maintains its elevation although not observable as a mountain range, being overcome 

 by easy grades. Notice the elevations of the railroad crossings of the Helderberg and Hamilton 

 range, although the railroad seeks the lowest points: Buffalo, 576; Batavia, 887; Le Roy, 864; Can- 

 andaigua, 778; Auburn, 715; Skaneateles, 890; Tully, 1249; Cazenovia, 1249; Cooperetown, 1193. 

 When the valleys cut through the limestone, the summit is farther south on the Hamilton or Portage. 



42. Lewiston. Tourists should not fail to go down to Lcwiston, the terminus of the Buffalo 

 and Niagara Falls division. This railroad ride, although little known, is one of the finest in the 

 United States. It follows the bank of the Niagara River, affording admirable views of the rapids and 

 the formations displayed in the gulf. Nowhere in the State are there better geological sections. 

 On the Canada side, also the Canada Southern Railway, running to the mouth of the Niagara River 

 at Niagara City, affords one good view of the falls, but no such remarkable sections of the rocks as 

 on the American side, where the railroad overhangs the fearful torrent of the river for several miles. 



43. Knowersville. The Helderberg mountain shows finely on the left or southwest side of the 

 railroad opposite Guilderland and Knowersville. The railroad passes through it between that place 

 and Duanesburgh. The mountain is capped by the 7. Lower Helderberg limestone forming a steep 

 precipice along its summit, and this rests on the 4 c. Hudson River slates. Back of Knowersville 

 two notches are cut out of the mountain by two streams, leaving a picturesque, fortress-like bluff of 

 the limestone. The Helderberg formations are named from this mountain. 



44. At Howe's Cave large quarries on the railroad track. Good place to examine Lower 

 Ilelderberg limestone and to collect fossils. The cave is an old underground water channel, "and is 

 several miles long. Notice that the limestone at Cobleskill is Upper Helderberg and that at 

 Howe's Cave Lower Helderberg. On no other railroad can you see them both. 



45. Cooperstown is seated at the south end of Otsego Lake on a a dike of alluvium. This lake 

 is a handsome sheet of water seven miles long, one and a half wide, 1193 feet above the ocean. It 

 has a high ridge of the Hamilton group on the east side, a low and interrupted range of the pame 

 on the west side, and an elevated projection on the northeast end. This lake is one of the head 

 waters of the Susquehanna, the valley spreading out to the southwest. 



46. Sharon Springs. All the large sulphur springs of the State, Avon, Clifton, Richfield, &c., 

 and many small ones, rise from the waterlime. 



47. Cherry Valley. The railroad is on Corniferous, but the cliffs and gorge are 7. Lower Helder- 

 berg. Marcellus and Hamilton form the hills on the south. 



