THE NONMETALLIC MINERALS. 171 



silica and iron oxide, with a little sulphur, magnesia, and alumina. 

 This graphite is regarded as originating through the metamorphism 

 of vegetable matter included in the original sediments, the agencies of 

 metamorphism being both igneous intrusions and the heat and pressure 

 incidental to the folding of the beds. 1 



As to so much of the graphite as occurs in beds there seems, then, 

 little doubt as to its origin from plant remains which may be imagined 

 to have existed in the form of seaweeds or to have been derived from 

 diffused bituminous matter. The origin of the vein material is not so 

 evident, though it seems probable that it is due to the metamorphism 

 of bituminous matter segregated into veins, like those of albertite in 

 New Brunswick or of gilsonite, etc., in Utah. Kemp states that the 

 Ticonderoga graphite must have reached the fissure as some volatile or 

 liquid hydrocarbon, such as petroleum, and become metamorphosed in 

 time to its present state. Walther believes the Ceylon material to have 

 originated by the reduction of carburetted vapors. (See also under 

 origin of diamonds, p. 166.) 



The total quantity of carbon in the form of graphite in the Lauren- 

 tian rocks of Canada has been estimated by Dawson as equal to that in 

 any similar areas of the Carboniferous system of Pennsylvania. 



Sources. The chief sources of the graphite of commerce are Austria 

 and Ceylon. Other sources of commercial importance are Germany, 

 Italy, Siberia (Specimen No. 61138, U.S.N.M.), the United States, and 

 Canada. The chief deposits of commercial value in the United States 

 are at Ticonderoga, New York, where the graphite occurs in a granu- 

 lar quartz rock, or, according to J. F. Kemp, in "Elliptical Chimneys 

 in Gneiss which are filled with Calcite and Graphite." An earth}', 

 impure graphite, said to be suitable for foundry facings, is mined near 

 Newport, Rhode Island (Specimen No. 53797, U.S. X.M.). About one 

 hundred years ago the material was mined in Bucks County, Pennsyl- 

 vania. Other American localities represented in the collections are 

 Bloomingdale, New Jersey (Specimen No. 56272, U.S.N.M.); Clinton- 

 ville, New York (Specimen No. 31597, U.S.N.M.); Hague, Warren 

 County, New York (Specimen No. 63132, U.S.N.M.); Raleigh, Wake 

 County, North Carolina (Specimen No. 63133. U.S.N.M.); Lehigh and 

 Berks counties, Pennsylvania (Specimens Nos. 66952; 66953, U.S. N. M. ) ; 

 Salt Sulphur Springs, West Virginia (Specimen No. 63423, U.S.N.M.); 

 St. Johns, Tooele County, Utah (Specimen No. 62721, U.S.N.M.). ' 



Graphite is a very common mineral in the Laurentian rocks of 

 Canada. The most important known localities are north of the Ottawa 

 River, in the townships of Buckingham, Lochaber, and Grenville 

 (Specimens Nos. 59976,. 51007, U.S.N.M.). At Buckingham it is stated 

 masses of graphite have been obtained weighing nearly 5,000 pounds. 



JJahrbuch k. k. Geologische Reichsanstalt, 1897, XL VII, p. 21. 



