104 REVIEWS 
to get at the essentials, the reader is often obliged to skim over many 
superfluous details on the optical properties of minerals. Some of the 
important conclusions may be open to the objection that they are based 
on insufficient evidence; namely, the great thickness and conformability 
of the sedimentary series, and the transfusion of certain materials from 
the granite gneisses to the limestones. Epwarp STEIDTMANN 
[Author’s Abstract] 
Production of Graphite in rgtrt. By Epson S. Bastin. Advance 
chapter from Mineral Resources of the United States, 1or1t. 
U.S. Geological Survey. 
The natural graphite mined and concentrated in the United States 
is variable in amount, principally because the process of milling flake 
graphite, the most abundant type of domestic material, is still in an 
experimental stage. Because of this unreliability of the domestic 
supply most of the large consumers of graphite prefer to depend for 
their supply on imported material. 
In 1911 the quantity of graphite imported into the United States 
for consumption was 20,702 short tons, valued at $1,495,729. In con- 
trast to this the total domestic production was 3,618 short tons of natural 
graphite, valued at $288,465, and 5,072 short tons of manufactured 
graphite, valued at $664,000. 
The great bulk of the graphite imported into the United States 
comes from the island of Ceylon, and the United States has for many 
years been the principal market for this Ceylon product. Considerable 
amounts of graphite are also imported into the United States from 
Mexico and within the last few years graphite from Chosen (Korea) 
has entered the market. 
The principal feature of this report as distinguished from previous 
reports on the production of graphite in the United States is a summary 
of existing knowledge in regard to the famous graphite deposits of the 
island of Ceylon. The literature concerning these deposits is widely 
scattered, mostly in obscure publications. The geological occurrence 
of the Ceylon graphite, method of working the deposits and of preparing 
the graphite for the market are discussed, and the various theories which 
have been advanced to account for their origin are summarized. A 
list of the principal publications dealing with these deposits is included. 
The report also describes a somewhat similar occurrence of graphite 
near Dillon, Mont., and concludes with a bibliography of all of the 
important publications dealing with the graphite deposits of the United 
States. 
