April 8d, 1871. 
The President in the chair. Thirty-two persons present. 
Dr. L. FEUCHTWANGER exhibited specimens of Silicified 
Wood, from the White Pine district in Nevada. Also a spec- 
imen of light-colored translucent Blende, from Spain. Also 
specimens of Marble, from California, Brandon, Vermont, and 
New York. 
Pror. B. N. Martin exhibited specimens of Crystallized 
Silver, from Lake Superior and Crystallized Gold, in which the 
form of the crystal was made up of fine metallic filaments, 
from Oregon. 
Pror. T. EanuEston remarked upon the beauty of the 
gold specimen, and said that although he was at first disposed 
to consider the silver crystals to be artificial, on subsequent 
examination he ascertained them to be natural and, as well 
as the gold, to present some points of considerable interest. 
Mr. B. G. AMEND exhibited a specimen of the White pul- 
verulent mineral, from Watertown, similar to that shown by 
Prof. Seeley at a previous meeting. He had found it to 
contain seventy-five per cent. of material soluble in acid. 
The following paper was read, 
On a Specimen of Ichthyosaurus. 
By B. WATERHOUSE HAWKINS. 
A good fossil specimen of the Ichthyosaurus or Fish- 
Lizard has arrived in this city, and is deposited in the Col- 
lege of the City of New York, which, in consequence of an 
invitation from the President, Gen. Webb, I have inspected. 
I did not measure the specimen, but it appeared to me a little 
over ten feet in length. It is in an excellent state of preser- 
vation, and has been compressed from below upwards, leaving 
it in a position to exhibit the. spinal column. The paddles, 
