360 The American Geologist. June, 1904. 
The western shore has not been discovered. In the most 
western Bragdon areas there are no traces of an approach to 
it. It may have been a narrow and discontinuous strip of land 
on the edge of the continental plateau. 
One of the most interesting features of this late Jurassic 
revolution is that it inaugurated deposition in California terri- 
tory under radically different conditions from those that for- 
merly obtained. The Triassic, early and middle Jurassic strata 
seem to have been deposited on the northeast side of a broad 
land area which occupied the site of the present Coast ranges, 
the western part of the Klamath region and most of the Sac- 
ramento valley region. After the revolution the site of this old 
land area was a territory subject to repeated submergences 
from the beginning of the Mariposa-Bragdon epoch to very re- 
cent times. During its second great depression, the Franciscan 
sediments were laid down, but between the Mariposa-Bragdon 
and the Franciscan epochs there seems to have been a long ero- 
sion interval. 
Las Pcrlas Minc^ Dovlcska, Calif., June 23, 1903. 
NOTE ON SOME CONCRETIONS IN THE CHE- 
MUNG OF SOUTHERN NEW YORK.* 
By E. M. Kindle, New Haven, Conn. 
During the progress of the survey of the \\'atkins Glen 
quadrangle, a bed of concretions which presents some unique 
features came under the writer's observation. This bed occurs 
in the Chemung sandstone, and is exposed in a quarry at Ross- 
burg a few miles southwest of Elmira, N. Y. The character of 
the beds associated with the concretions is shown by the section 
of the beds associated with the cocretions is shown by the sec- 
tion of the quarry which follows : — 
8. Tliin-bedded sandstone and shale . . .10 ft. 
7. Sandstone with nnmerous concretions . . 2 it. 
6. Drab colored shale . . . . . . i ft. 
5. Sandstone o' to i ft. 
4. Gray shale . ' . . . . • . 6 ft. 
3. Heavy bedded gray sandstone, of even textnrc. chang- 
ing in the north part of the quarry to a bed of con- 
cretions of large size . . . . 5' to 6 ft. 
* Published by permission of tbe Director of the U. S. Geological Survey. 
