March 5th.—A severe shock of earthquake at San Francisco at 8h. 49m. M. The first wave had a north and south direction and continued 1¾ seconds; nearly 1¾ seconds elapsed before the second shock, which was at 8h. 49m. 3s., and continued 1½ seconds. The second shock was rotatory; the pendulum swinging north and south from the first shock, began and continued to describe a short oval or nearly a circle from the effects of the second shock, and continued thus for more than half an hour, until stopped and brought to rest. Magnetism was not suspended in this earthquake, nor any other that has occurred since my instrument was suspended. These observations were made at the height of twenty feet four inches from the ground. The total of time included in the shock was nearly five seconds. The farthest point south to which I have been able to trace its effects is the Mission San Juan, and north to Sacramento, a distance inclusive of 177 miles. In an easterly direction we have not traced it east of Stockton, about 60 miles. It was felt at Santa Clara, Santa Cruz, Gilroys, south of San Francisco, and at Santa Rosa and Petaluma to the north. Since the above was in type, advices have been received from Visalia. At that locality the shock was very smart. The first shock took place at 8h. 45m. M., being four minutes earlier than that at San Francisco. This gives for the entire distance, north and south (over which the earthquake extended), 257 miles. This extent of latitude, and the almost simultaneous period of time at which it was observed along the entire line of distance so far as heard from, leads to the conclusion that its probable centre was south of San Francisco and nearly in the same longitude. From the violence of its action I feel inclined to the belief that its centre was in the neighborhood of San José, for all accounts agree in this one point, that more turbulence of the earth’s surface occurred in this region during its continuance than at any other place yet known. At Visalia the first shock was a mere tremor, but was followed by an undulatory movement when the second shock occurred, which was some three or four seconds later. This wave moved in an east and west direction at that place. REGULAR MEETING, MARCH 21ST, 1864. Dr. Trask in the Chair. Eleven members present. Messrs. J. G. Kellogg and Jacob Deidesheimer were elected resident members. Resolutions were passed in memory of the Rev. T. Starr King, late a member of the Academy, and a copy directed to be forwarded to the family of the deceased. Donation to the Library: “Descriptions of New Species of Tropical American Birds,” by Geo. N. Lawrence, extracted from the Annals of the New York Lyceum, by the author.