HISTORY OF PETEOLEUM OE ROCK OIL. 321 



state. It is very pulverulent, brittle, of a shining black, and accord- 

 ing to Vanuxem yielded but little ash, and 11| per cent, of volatile 

 matter, which he regarded as water, (Yanuxem, Geology of New 

 York, iii, 33.) A similar material occurs in the Quebec group in 

 Canada, the equivalent of the calciferous sandrock, and fills cavities 

 and fissures in the limestones, sandstones, and even in the accom- 

 panying trap rocks, as at Quebec, Orleans island. Point Levis, and at 

 Acton, presenting mamillary surfaces as noticed by Vanuxem, which 

 evidently show that it has once been semi-fluid. This matter from 

 the first two localities is completely infusible, and insoluble in benzole; 

 it readily crumbles between the fingers and gives a very black powder. 

 When exposed to a high temperature it gives off' abundance of in- 

 flammable strong-smelling vapors, which condense into a tarry oil, 

 and leave a black residue, which when heated slowly burns away, 

 leaving only a trace of ash. The volatile portion is equal to from 

 19.5 to 21.0 per cent. The mineral from the Acton copper mine is 

 much harder and less friable, and approaches to anthracite in its 

 characters. "When heated it gives off watery vapor without any 

 bituminous odor. Its loss by heat was 6.9 per cent., and the residue 

 of ash was equal to 2.2 per cent. 



An evidence of the presence of unaltered petroleum in almost all 

 the Lower Silurian limestones is furnished by the bituminous odor 

 which they generally exhibit when heated, struck, or dissolved in 

 acids. In some cases petroleum is found filling cavities in these lime- 

 stones, as at Riviere a la Rose (Montmorenci,) where it flows in drops 

 from a fossil coral of the Birdseye limestone, and at Pakenham, where 

 it fills the cavities of large orthoceratites in the Trenton; from some 

 specimens nearly a pint of petroleum has been obtained; it is also 

 said to occur in the township of Lancaster in the same formation. 

 The presence of petroleum in the Lower Silurian rocks of New York 

 is shown in the township of Guilderland, near Albany, where, accord- 

 ing to Beck, considerable quantities of petroleum are collected upon 

 the surface of a spring which rises through the Hudson river or 

 Loraine shales. On the Great Manitoulin island, also, according to 

 Mr. Murray, a petroleum spring issues from the Utica state, and he 

 has described another at Albion Mills, near Hamilton, rising through 

 the red shales of the Medina group; these have probably their origin 

 in the Lower Silurian limestones, which may in some localities prove 

 to be valuable sources of petroleum. 



In the Upper Silurian and Devonian rocks bitumen is much more 

 abundant. Eaton long since described petroleum as exuding from 

 the Niagara limestone; and this formation throughout Monroe county, 

 in western New York, is described by Mr. Hall as a granular crystal- 

 line dolomite including small laminae of bitumen, which give it a 

 resinous lustre. When the stone is burned for lime the bitumen is 

 sometimes so abundant as to flow like tar from the kiln. In the cor- 

 niferous limestone at Black Rock, on the Niagara river, petroleum is 

 described as occurring in cavities, generally in the cells of fossil 

 corals, from which, when broken, it flows in considerable quantities. 



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