i82 The American Geologist. March, i899 
exist. Nowhere does the channel appear to be narrower than 
three-fourths of one mile. The w'idth of the chief tributary 
seems comparable with the main channel. It is possible that 
what is regarded as the chief tributary may be the principal 
channel, and vice versa. 
Southeast of Anna few deep wells have been sunk, and 
the water wells do not reach the rock. Consequently the 
channel cannot at present be traced beyond that point. It is 
(jf interest to note here, however, that at St. Paris, in the west- 
ern part of Champaign county, a deep well was sunk some 
years ago, and drift to a depth of 530 feet was passed through 
without reaching rock. This may lie in the main channel. 
Dcpartjiicnt of Geology, Ohio State University. 
THE OCCURRENCE AND ORIGIN OF DIAMONDS 
IN CALIFORNIA.* 
By H. W. Turner, Washington. 
it has long been known that diamonds are occasionall\" 
found in the gold placer deposits of California. Prof. J. D. 
Whitney f and Prof. Hanks have recorded such localities 
where diamonds have been found as came under their notice. 
Professor Whitney writes: 
"The most interesting mineral found associated with the gold in the 
gravel of California is the diamond. This gem, as it would appear, is 
usually, although not universally, found in gravels which are washed 
or searched with care. Such gravels are chiefly those which are 
auriferous in character. Hence it follows that diamonds have been 
found in the surface detritus of most gold regions, as in Siberia. 
Australia, along the flanks of the Appalachian chain, and in California. 
* * * It appears that diamonds, like some other natural products, 
are widely disseminated over the surface of the earth, but are only 
present in considerable quantity at a very few points. Formerly, India 
was the productive region; then Brazil had its day; and now South 
Africa furnishes by far the larger portion of the new diamonds put 
upon the market. * * * 
The diamond has not been found in sufficient quantity anywhere in 
North America, whether in the Appalachian or the Californian gold- 
fields, to be of much importance from an economical point of view. 
♦Published by permission of the Director of the U. S. Geol. Survey. 
tAuriferous gravels of the Sierra Nevada. 1879, pp. 362-364, and 
Pr(,f. Hanks' 4th Ann. Rep. State Mineralogist, 1884, pp. 159-172. 
