1872.] 185 [Kneeland. 
Mollusks. Insects. 
EpWARpD S. Morsz, F. G. SANBORN, 
Jonn CUMMINGS, © A. 8. Packarp, Jr., M.D., 
LEviI L. THAXTER. EpWARrp BURGESS. 
Fishes and Reptiles. Birds. 
F. W. Purnam, THomAS M. BREweER, M.D., 
D. H. Storer, M.D., SAMUEL Cabot, M.D., 
S. KnEELAND, M.D. J. A. ALLEN. 
Mammals. Microscopy. 
J. A. ALLEN, . EDWIN*BICKNELL, 
THOMAS WATERMAN, JR., M.D. R. C. GREENLEAF, 
J. B.S. JACKSON, M.D. B. Joy JEFFRInS, M.D. 
May 15, 1872. 
The President in the chair. Thirty-three persons present. 
Dr. 8. Kneeland read extracts from a letter from Mr. John 
Muir, on the effects of the earthquake of March 26, 1872, in 
the Yosemite Valley. 
The earthquake storm in the Yosemite began Tuesday, March 26, 
1872, at 21-2 a.m. People wereshaken out of bed, and the floors shook 
like the deck of a vessel at sea. First shock lasted about three minutes 
and with great energy and motion, undiminished to the end. For 
the first minute no sound but the agitation of the trees. Expected 
“ Sentinel Rock,” a high isolated pinnacle, would fall, but at last 
from the south side of the valley opposite Yosemite falls, there came a- 
tremendous sound. Eagle Rock had fallen two thousand feet, and 
was pouring in an avalanche of boulders over precipices, and through 
forests of fir and spruce, filling the valley with a smoke of fire and 
rock dust, and countless reverberations and echoes. Sky clear and 
moon bright, so that the outlines of the rocks, trees and meadows 
could be plainly seen; trees greatly agitated, in strange, indeterminate, 
motions; frogs silenced for the time, but before the dust had settled, 
or the echoes had died away, an owl began to hoot from the very 
edge of the fallen rocks, as if unconscious of any extraordinary dis- 
turbance. River soon after was found to be muddy from portions of its 
banks shaken into it, but otherwise flowed as peacefully, in the same 
direction, as ever. Upper Yosemite did not seem to show the slight- 
test agitation. 
