300 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213; 
with a conchoidal fracture, and heavier than water. Toward a tem- 
perature of 300° C. it becomes soft and elastic. It begins to decom- 
pose before it melts, and burns like the resins, leaving an abundance 
of coke. 
Dana, in his System of Mineralogy, quotes several analyses of 
petrolene by Boussingault, one of which gives C. 87.45, H. 12.30.. 
DISTRIBUTION OF THE ASPHALTS AND BITUMINOUS ROCKS OF 
THE UNITED STATES. 
The distribution of asphalts and bituminous rocks in the United ; 
States is wide. The asphaltites are found in West Virginia, Indian 
Territory, Colorado, and Utah; bituminous limestones in Indian Ter- 
ritory, Texas, and Utah; bituminous sandstones in Kentucky, Mis- 
souri, Indian Territory, Texas, Utah, and California; a earthy bitu- 
men of greater or less purity, occurring as veins, in California; while 
brea may occur in all petroleum areas, but in the present investiga- 
tion was found only in Indian Territory, Wyoming, and California, 
although small bodies are reported in Montana. 
The stratigraphic range of the bitumens and their compounds is as 
wide as their geographic distribution. Their oldest association | 
observed is with the Ordovician shale of the Tenmile region in eastern 
Indian Territory, where impsonite, an asphaltite closely related to 
albertite, occurs in vein form. Other veins of like material, as well 
as a bituminous sandstone, occur in the series of Ordovician sand- 
stones overlying the shales along the Indian Territory- Arkansas line. 
In central Indian Territory, in the Buckhorn district, are other bitu- 
minous sandstones, also of Ordovician age, though perhaps not to be 
correlated with the foregoing. Above these, in direct succession, is 
the summit limestone of the Ordovician, at least for this locality — a 
massive bed of variable thickness, the maximum being approximately 
400 feet. The entire body of rock is varyingly impregnated with bitu- 
men, the more highly enriched portions to an average of 6 to 8 per 
cent. In this same locality the Lower Coal Measures also, at one or 
more horizons, are richly infiltrated with bitumen, one of their lime- 
stones carrying an average of 14 per cent. The Lower Coal Measures 
are unconformable with the underlying formations, and the occur- 
rence of bitumen at the several horizons suggests a common source and 
origin for it, and an inflow to its present reservoirs, perhaps subse- 
quent to the laying down of all the sediments involved, if not, indeed, 
subsequent to their folding. On the other hand, from the presence 
in the Coal Measure conglomerate of an occasional pebble, believed to 
be of Ordovician bituminous sandstone, particularly observed by Mr. 
Taff, there may have been two or more distinct flow periods. 
West and south of the Arbuckle Mountains the Coal Measures again 
a Since the writer's field investigation indefinite accounts of bituminous sandstones in Alabama 
and Illinois have appeared in certain newspapers. 
