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334 PROCEEDINGS OF SCIENTIFIC SOCIETIES. 
CALIFORNIA ACADEMY OF NATURAL SCIENCES. San Francisco, May 
6, 1867. — The Committee on Field Excursions reported in reference to 
the recent excursion to the Twelve Mile Farm, on the San José Road. 
the above place,—a blue sandstone, which is undergoing decompo- 
Sition, containing many species of shells o = — forms, many 
e as living species, accordin Mr. Stearns. Prof. 
Waor remarked upon the aingulariy i is olated sation of this out- 
traces of it many miles beyond, but did not suc e fact was 
one of many evidences going to show the extensive denudation that 
had occurred in this part of the State ehr presented a chrysalis 
dergo a metamorphosis or change from the grub state, while the mate 
is the same as other moths 
Mr. Stearns submitted, on behalf of Mr. J. Rowell, a description 
of a new species of Pisidium, a genus of fresh-water bivalves, found 
ich 
moon were infallible signs of r His ervations proved that in 
some seasons these signs biei failed in — and at the 
T no rule, he thought, could be established on the subject. 
r. Goodyear read a paper by Prof. Silliman, Sa new localities 
ie roe monds. One from French Corral weighed 5.114 grains, equal 
to 1} carats, symmetrical in form, and slightly yellow in color from 
being subjected to a fire test. It was found in the gravel washings- 
The second specimen is from Diets Hill, El Dorado [Placer ?] county; 
weight 5.673 grains, equal to nearly 14 carats; color good, but less 
- the ape: Since 1855 five. diamonds are known to have been 
h over a carat. All were found, 
. in a gray, cemented gravel iS a stratum of lava or comp 
olcanic 
v ashes. The fourth specimen is from Cherokee Flat, Butt 
pep ange which has a some reputation as a diamond locality. It 
cut and set in a ring. 
_ Prof. Whitney remarked that there are fifteen localities in Califor- 
nds 
bid a which dinni | have been found in the course of washings for 
