by Dr. T. Sterry Hunt. 245 



lime the bitumen is sometimes so abundant as to flow like tar 

 from the kiln. In the Corniferous 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. It also occurs in similar condi- 

 tions in the Cliflf limestone (Devonian) of Ohio. 



Higher still in the series, at the base of the Hamilton group, 

 occur what in New York have been called the Marcellus shales ; 

 these enclose septaria or concretionary nodules which contain pe- 

 troleum, while at the summit of the same group similar con- 

 cretions holding petroleum are again met with. Tha sandstones 

 of the Portage and Chemung group in New York are in many 

 places highly bituminous to the smell, and often contain cavi- 

 ties filled with petroleum, and in some places seams of indurated 

 bitumen. A calcareous sandstone from this formation at Laona 

 near Fredonia in Chatauque county contains more than two per 

 cent of bituminous matter. At Rockville in Alleghany county, 

 according to Mr. Hall, the same standstones are highly bitumin- 

 ous and give out a strong odor when handled, and in the counties 

 of Erie, Seneca and Cataraugus abundant oil springs rise from the 

 sandstones and have been known to the Seneca Indians from an- 

 cient times. In the northern part of Ohio, according to Dr. New- 

 berry, petroleum is found to exude in greater or less quantity from 

 these sandstones wherever they are exposed, and the oil wells of 

 Pennsylvania and Ohio are sunk in these Devonian sand- 

 stones, often through the overlying carboniferous conglomerate, 

 and in some cases apparently, according to Newberry, through the 

 sandstones themselves, which are supposed by him to be only 

 reservoirs in which the oil accumulates as it rises through fissures 

 from a deeper source, in proof of which he mentions that in boring 

 wells near to each other, the most abundant flow of oil is met with at 

 variable depths. In some instances the petroleum appears to filter 

 slowly into the wells from the porous strata around, which are satu- 

 rated with it, while at other times the bore seems to strike upon a 

 fissure communicating with a reservoir which furnishes at once 

 great volumes of oil. An interesting fact is mentioned in this 

 connection by Mr. Hall. In the town of Freedom, Catarragus 

 Co., New York, is a spring which had long been known to 

 furnish considerable quantities of petroleum. On making an ex- 

 cavation about six yards distant, to the depth of fourteen feet, a 

 copious spring of petroleum arose, and for some time aff'orded large 



