of
the Pacific coast and the Atlantic States have been derived by erosion
from the adjacent mountain ranges, but the original sources have never
been discovered. Those of the northern drift have doubtless come from
beyond our borders, in Dominion territory, and their exact source is
entirely a matter of speculation. The few occurrences in Tennessee and
Kentucky are not as yet definitely traceable, even in theory. All have
been found in loose and superficial deposits, and all acciilentally.
Most of those in the Atlantic and Pacific regions have been met with in
washing for gold.
This
subject of the occurrence of diamonds in the United States has been
Treated in some detail by the writer in a report to the United States
Geological Survey, to be issued in the near future.
SEARCH FOR DIAMONDS IN BLACK SANDS OF THE UNITED STATES.
The
high price of diamonds has made the search for these precious stones in
the United States and Canada keener than ever before. In the
examination by the United States Geological Survey of many samples of
gold and platinum sands during the Lewis and Clark Exposition at
Portland, Oreg. diamonds were carefully looked for. Diamonds have been
watched for also by a number of parties that have been dredging for
gold on an extensive scale in the rivers of California, but in neither
case have any finds been reported.
INDIANA.
Minerals
of the Indiana drift in relation to their supposed Canadian source.—
The only well-attested diamond discoveries in the drift region of the
United States during the last four years have been those in connection
with the gold washings of Brown and Morgan counties, in southern
central Indiana. The writer has taken special pains to obtain a full
series of specimens of the rocks and minerals found in the gold-bearing
drift of this region from Mr, George C. Royce. of Martinsburg. \V. Va.,
and Professor Blatchley, State geologist of Indiana, and others, for
the purpose of having them compared with the rocks in Canada, north of
the Great Lakes, with a view to tracing out, if possible, the source
whence the diamonds came.
With the hope of aiding
in the solution of this problem the collections of drift minerals and
rocks from the diamond section of Indiana were sent to Canada for
examination and were laid
before the Ottawa meeting of the Geological Society of America in
December. 1005. Considerable discussion was awakened, lint no very
definite results have as yet been reached.
Among
those who examined the specimens at the meeting with particular
interest and expressed opinions thereon are the following Canadian
geologists : Dr. A. E. Barlow. Mr. W. J. Wilson, and Prof. II. M. Ami,
of the geological survey of Canada: Prof. W. G. Miller, of the Ontario
Bureau of Mines; Dr. G. A. Young, petrographer. and subsequently in
more detail, Prof. Frank D. Adams, of McGill University, at Montreal.
All these gentlemen were especially qualified to judge of these
materials by intimate acquaintance with the geology of the region under
consideration and its glacial phenomena.
Doctor
'Barlow and Mr. Wilson recognized a number of the fragments in the
collection from the Indiana drift as apparently identical with rocks
familiar to them at various points in northern Ontario. Especially
marked was the prevalence of pieces and rolled pebbles of jasper and
jaspilite, characteristic in association with the iron ores of the
Michipicoten and other iron ranges north of Lake Superior.
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