THE MINING AND QUARRY 



INDUSTRY 



149 



In Rensselaer county there is a formation known as the Rensset"- 

 aer grit. Like the Shawangunk grit it has usually been correlated 

 with the Oneida conglomerate, but it probably belongs to a much 

 'higher horizon. The Rensselaer grit is unfavorably situated for 

 'transportation facilities and no quarries of importance are operated 

 in this formation. 



Clinton sandstone. This formation follows directly above the 

 Medina. It consists of limestones, shales, sandstones and beds of 

 iron ore. The rocks extend from Otsego county west to the 

 Niagara river. In western New York sandstones are not found 

 in this formation, but in the eastern section they constitute an 

 important part of the grpup. The most extensive sandstone ledges 

 are found in the Mohawk valley from Ilion to beyond Utica. The 

 rock that is quarried consists of reddish brown and gray sand- 

 Stones. It is quite hard and even grained and is suitable for nearly 

 all kinds of construction work. A ledge 40 to 50 feet thick is 

 found at the top of the formation. This stone is used considerably 

 for foundation work in L'tica and other near-by places. Several 

 of the church buildings in Utica are built of this stone. 



Devonic sandstones. The lov, est sandstone formation of the 

 Devonic is the Oriskany. This is a well known formation and is 

 about 20 feet thick. It is best developed in eastern and central 

 New York. In the western part of the State, when found, it 

 occurs only as a thin bed and in some places it is entirely absent. 

 The outcrop of the Oriskany follows approximately that of the 

 Helderbergian escarpment. On account of the rock being some- 

 what friable, it is but little used for construction purposes. 



In the Upper Devonic, the Hamilton, Portage, Chemung and 

 Catskill formations comprise a great series of alternating beds of 

 sandstones and shales that are developed throughout the central 

 and southern parts of the State and occupy approximately one 

 third of the entire area. The northern and eastern limit of this 

 area is approximately defined by a line passing from Port Jervis 

 in Orange county, northeastwardly to Kingston and along the west 

 side of the Hudson river to a few miles below Albany, and then 

 extending in a broad curve to the north of west, passing a short 

 distance south of Syracuse and almost directly westward to Lake 

 Erie. An outlying area of Middle Devonic rocks is found; in. 

 Orange county. The rocks consist of coarse beds known as the. 

 Bellvale flags and the Skunnemunk conglomerate. A limited area 

 of rocks of Carbonic age is found in Allegany and Cattaraugus 

 counties. The sandstone of the Devonic formation is popularly 



