134 GEOLOGY OF THE TmRD DISTRICT. 



which faces the Mohawk valley, shows that for a long time it was the bottom of a river or 

 flow of water ; and the vertical joints being greatly enlarged, exhibit separations, a few of 

 which are two and three feet wdde ; the surface presenting in one place a series of insulated 

 gigantic blocks, arranged in regular order, and in conformity to the direction of their joints, 

 evidently the result of solution and wear by water, and presenting in all respects the same 

 phenomenon observable on Cincinnati creek and Sugar river from the points where their 

 waters respectively disappear. 



A notice of the discovery and importance of this limestone as a marble was published many 

 years ago in the Cherry- Valley Gazette, and it was described as being like the Potomac mar- 

 ble used at Washington. The fossils probably were taken for pebbles, and the green coating 

 between the courses, and which gives a greenish color to portions of it, completed the sup 

 posed identity. The Potomac marble belongs to the New red-sandstone, whose origin was 

 subsequent to the Coal ; the latter mass being placed between the New red-sandstone, and 

 the Catskill group. 



The Onondaga limestone takes a good polish, and is used at the village as a marble, and as 

 a building stone. It is quarried at the bottom of the valley near the village. The stone there 

 has a fresher or less altered surface than at its north end, where it is much weathered and 

 discolored. When fresh quarried, it is of a light grey, its grain small and coarse ; the latter 

 is easiest to work, the former being tough : some parts have a pink hue. 



A level was made from the surface of this valley, which commences on the top part of the 

 Onondaga limestone, to the Mohawk river, and found to be twelve hundred feet. This height 

 will give some idea of the change which has taken place in that valley since the waters flowed 

 over the Onondaga limestone, which forms the bottom of the valley. The north outcrop of 

 the limestone, which appears at the edge of the great valley, shows a flow of water north, 

 just as exists now in every valley west of Sauquoit creek inclusive. The surface towards the 

 village of Cherry- Valley, and the excavation of the valley, show, on the contrary, a flow of 

 water south ; and the latter is fully confirmed by the enormous quantity of northern drift in 

 the form of pebbles, boulders, etc. which extend along the valley throughout its whole course. 

 Like all the other rocks, the Onondaga limestone dips to the south, which is well observed at 

 Cherry- Valley. It is probable that the dip increases at no great distance from where it dis- 

 appears, which would more readily account for higher rocks in the series presenting them- 

 selves at the levels where they appear ; a circumstance noticed in other valleys further west, 

 Bridgewater valley for example, though it may be admitted that the fact is but in appearance 

 only. 



Fossils are quite numerous at this locality : most of those before enumerated were found, 

 the Elongated pentamerus being abundant, but not well preserved. 



The Onondaga limestone is quarried as a marble on the road to Cooperstown in the town 

 of Springfield, by Mr. Grout. There arc but few layers opened ; the stone is of good quality, 

 and is handsome when polished. The large encrinal stems are numerous, and often partiaHy 

 of a pink color. 



