ACADEMY OF NATURAL SCIENCES. 191 



this place, occurred at 18 h. 57 m. At Sacramento the shocks occurrecrTrt 18 h. : 

 and was very severe. There were two distinct waves felt at this locality. This 

 earthquake was felt as far north as Long Valley, in Mendocino County, ! nd was 

 followed by two loud reports like artillery, almost instantly. 



June 6th, 11 h. 7 m. — A light shock of earthquake at San Francisco. 



Junk 22d, 20 h. 53 m. — A smart shock of earthquake at San Francisco, con- 

 sisting of three distinct waves and a profound low rumbling sound. Each of the 

 shocks were marked by a peculiar abruptness, like sudden sharp jolts. They 

 were followed by a series of lessening tremors which gradually died away. 



This earthquake was felt as far north as Healdsburg, (about 80 miles distant), 

 at Napa, at Pacheco, at Stockton, and at San Jose, south of this city fifty-two 

 miles, making a distance of one hundred and thirty-two miles, north and south, 

 over which its influence was well marked. 



July 5th, 20 h. 3 m. — An earthquake at San Francisco, not severe ; this con- 

 sisted of four distinct vibrations occurring during a period of seven minutes. The 

 second vibration and the longest lasted nineteen seconds. The shortest vibration 

 was six seconds in length. The elapsed time between the waves varied from 

 forty seconds to one and one-fourth minutes. 



July 2Jst, 2 h. 7 m. — A smart shock was felt at San Francisco. 



" " 22 h. 40 m. 38 s. — Avery smart shock of earthquake at San Fran- 

 cisco, consisting of two waves at four seconds apart. The direction of the motion 

 was north thirteen degrees east. The displacement was one and a fourth inches, 

 at twenty feet four inches from the ground. Pendulum suspension eighteeu in- 

 ches. 



The earthquake was experienced at San Jose at the same hour, and consisted 

 of four strong shocks; At Stockton the earthquake was severe, and took place 

 twelve minutes later than at this city. The earthquake was felt at Los Angeles, 

 but was not very heavy. No time is given from this latter locality. 



July 25th, 23h. 56 m. — A shock of earthquake at Los Angeles. 



Aug. 17th, 22 h. 39 m. — A light shock of earthquake at Nevada and vicinity. 



Aug. 18th, 5 h. 18 m. — A very strong shock of earthquake was experienced at 

 Grass Valley and Nevada, which threw down a wall of stone and brick in the 

 well of Dr. Fellows. This earthquake was felt at Gibsonville at the north and 

 at Marysville to the west; at the latter locality it was twelve minutes later than 

 at Grass Valley. 



Sept. 6th, 10h. 3 m. — A shock of earthquake at San Francisco. 



Sept. 20th, 11 h. m.— A light shock of earthquake at San Jose ; it was ob- 

 served at the Mission Dolores. 



Sept. 27th, 10 h. 32 m.— A heavy shock at Mission San Juan, Monterey Co. 



Oct. 6th, 21 h. 9 m. — A smart shock of earthquake at San Francisco. 



Oct. 14th, 1 h. 8 m. — Two heavy shocks of earthquake were felt at Mission 

 San Juan, and another severe shock at 10 h. 25 m., the movement was from west 

 to east. 



Dec. 11th, 20 h. 52 m. — A shock of earthquake at San Francisco. This shock 

 was felt at San Jose at 90 h. 51 in., and was evidently more severe there than at 

 San Francisco. 



During 1864, we have had twenty-one days on which earthquakes have occurred, 

 and of (fiat number there have been two days, (March 10th and July 21st) in 



