326 The American Geologist. May, 1899 
azite occurs as minute crystals coating feldspar.Viornblende and corun- 
dum and intimately associated with the wellsite, in a corundum mine 
in Clay county. Two analyses are given; and the ratio of AI2O3 to the 
protoxide bases is found to be somewhat below the normal. The an- 
thophyllite, which occurs in dunite rock near Bakersville, was original- 
ly described by Penfield in 1890, before the locality was known. A 
new analysis is given, and Penfield's analysis is quoted for comparison, 
the two agreeing very closely, and closely approximating the normal 
composition. The enstitite forms rock masses bordering the dunite of 
Corundum hill. The analysis indicates the admixture of 35 per cent 
of serpentine and 20.5 per cent of talc, the pure enstatite forming but 
44.5 per cent of the whole. The bronzite forms with an emerald-green 
diopside a tough rock (websteryte) in the dunite of the Tuckaseegee 
valley; and the websteryte also varies to a nearly pure bronzite rock. 
The analysis and physical characters show this to be a very typical 
bronzite. The emerald beryl occurs in a vein of pegmatyte, and is in 
part of gem quality; but it has not been analyzed. All of the new 
analyses of the foregoing minerals were made by Chas. Baskerville of 
the N. C. Geological Survey. w. o. c. 
The Origin and Chemical Composition of Petroleum. A Symposi- 
um. By S. P. Sadtler, S. Y . Peckham, David T. Day, Frances C. 
Phillips and Charles F. Mabeky. Proc. Am. Phil. Soc, 36, 93-140. 
This paper is a valuable summary of our knowledge of petroleum 
and natural gas, and in a measure of all of the native bitumens. Prof. 
Sadtler discusses the genesis and chemical relations of petroleum and 
natural gas; and rejecting all the theories of the inorganic origin of 
these bodies, and weighing carefully the rival theories of their deriva- 
tion from animal tissues and from plants, concludes, partly from orig- 
inal experiments with linseed oil, that both the theories of their organic 
origin are required to explain all the facts. Prof. Peckham's contribu- 
tion is on the nature and origin of petroleum, setting forth at some 
length the facts which appear to sustain the distillation theory, which 
is made to cover all the native bitumens from natural gas to asphaltum. 
Dr. Day develops a suggestion as to the origin of Pennsylvania petro- 
leum which is a modification of Mac Gonigle's theory that the Pennsyl- 
vania oils have been derived by distillation from the underlying Silurian 
strata, the transfer from the lower to the higher formations, with a not- 
able increase in density and loss of sulphur, having, according to Day, 
been accomplished, not by distillation but by an upward filtration 
through beds of shale. Prof. Phillips discusses and accepts provisional- 
ly MendeleeiT's theory that metallic carbides have been produced deep 
in or below the earth's crust, and that these carbides have been de- 
composed by steam, giving rise to the various hydrocarbons of oil 
and gas; and in accordance with this view the author argues strongly 
against the view that petroleum occurring in the cavities of fossils is 
indigenous in them. Prof. Mabery, in considering the composition of 
American petroleum, notes the progress of our knowledge, the diffi- 
culty of correlating the composition or specific gravity with the dis- 
