MINERAL RESOURCES OF THE STATE OF NEW YORK IQ 



array of sediments — shale, sandstones, conglomerates and lime- 

 stones in varying order — arranged in successive layers or sheets 

 one above the other from the base to the top. Underlying the 

 whole series is the Precambrian basement of granite etc. which has 

 its outcrop in the Adirondacks and the province of Ontario on the 

 north side and the Highlands on the east. The thickness of the 

 sedimentary series increases progressively to the south and southwest 

 in which direction they incline at an average rate of around fifty feet 

 to the mile. From the Adirondacks to the Pennsylvania border 

 the sequence follows in ascending order, beginning with the Cam- 

 brian and continuing through the Ordovician, Silurian and Devonian 

 systems as given in the table on a preceding page. 



The surface of this province presents greater contrasts of elevation 

 than any other. The lowest parts, along the Mohawk valley and 

 on the Lake Ontario plain, are only 200-300 feet above sea level. 

 To the north of the Mohawk the surface rises rather steeply to the 

 Adirondack foothills, where the sedimentary terrane extends up 

 to altitudes of 500 to 2000 feet; in this part the Paleozoic rocks 

 locally are broken into blocks by faults and have been isolated 

 on the crystalline basement so as to form inliers more or less remote 

 from the main area. The extreme altitudes are reached in the 

 Catskills where the peaks are a little over 4000 feet. The rocks there 

 are not folded or displaced to any wide extent; the mountains 

 are simply the more dissected part of the southern plateau that 

 reaches across the State from the Hudson to Lake Erie. This 

 plateau is composed of a monotonous succession of Devonian sand- 

 stones and shales and is bounded northward by the Onondaga 

 escarpment which marks the descent to the Mohawk valley and 

 the Lake Ontario plain floored by Silurian and Ordovician sediments. 



The mineral deposits include few of secondary origin. The low- 

 dipping, almost unbroken sedimentary terrane has not been favor- 

 able to extensive vein accumulations. Among the ores the Clinton 

 hematite is the only representative of any considerable importance. 

 It is one of the constituent layers of the Clinton formation which 

 otherwise is made up of sandstone, shale and limestone, and is 

 found along the outcrop of the beds from Oneida to Monroe county, 

 disappearing to the south under cover of the higher strata. The 

 layers are thin but cover wide areas and altogether constitute a 

 very large acctimulation of the ore. In appearance it differs from 

 any of the other iron ores of the State, having either a fossil or 

 oolitic habit, in accordance with the particular conditions of its 

 deposition which took place at the surface contemporaneously with 



