82 



Creek and the northeast part of Nevada county. 



April 7, 6 P. M.— A light shock was felt at Gibb's 

 Ferry, Trinity county, and was experienced as far 

 north as Callahan's Ranch, at the head of Scott's 

 Valley. Siskiyou county. 



June 25, 2 P. M. — A smart shock was felt at Santa 

 Barbara, and extended northward as far as the val- 

 ley of Santa Maria. This shock wascotemporaneous 

 with one that occurred in Switzerland. 



July 10. 9A A. M.— A light shock was felt in 

 Georgetown, El Dorado county, which lasted about 

 four seconds. On the same day a very severe shock 

 was felt in the city of Los Angeles, which done con- 

 siderable damage. There were four distinct shocks 

 during the earthquake, with a period of about two 

 or three seconds, elapsing between each vibration. — 

 During their continuance, the ground opened in sev- 

 eral places, in fissures of one or two inches, the marks 

 of which remained for several days afterwards. — 

 There were some twenty-six buildings in the city 

 more or less injured, which I personally examined, 

 and among them the church, the west wall of which 

 w;ts split from top to bottom in two places, the fis 

 -ures being from one to ' two and a half inches in 

 breadth, running entirely through. The east wall 

 split at a slight angle from the perpendicular, and 

 had but one fissure. The walls of the Star Hotel 

 were split in several places, and on the west side 

 there appears to have been a decided horizontal mo- 

 tion, as the wall was displaced on that side horizon 

 tally to the depth of about one inch, and some eight 

 or nine feet in length. The amount of displacement 

 decreased from the west end of the building towards 

 the centre. It is a fact worthy of note, that none of 

 the thin adobe walls of the buildings suffered injury, 

 while most of the thick walled buildings were injured 

 to a grtater or less extent. 



During the earthquake, many articles were thrown 

 down, those that were standing on shelves against 

 the cast end of the buildings were thrown westward 

 on to the floor, and those on the opposite end of the 

 buildings were thrown back in an inclined position 

 against the walls. These features were noticed in I 

 the drug stores of Doctors Winston and Hope, situa- j 

 ted on the main street, and a short distance west of! 

 the church. 



The meteorological condition of the atmosphere 

 was rather unusual, and is described as follows : — 

 The day was unusually warm and sultry, attended 

 with little thunder and some rain, (the latter very 

 unusual) and a very sudden change of temperature 

 to unpleasant coldness. At Point San Juan there I 

 was observed considerable commotion in the water, 

 attended with a strong ruRhing sound, and two un- 

 usually heavy surf swells immediately following the 

 last shock. 



_ This shock was felt distinctly at the saw-mill some ] 

 sight miles east of San Bernardino, about seventy 

 miles east of Los Angeles, and at Santa Barbara, 

 about one hundred miles in a westerly direction. At 

 Los Angeles the shock occurred at fifteen minutes 

 after eight in the evening. 



Aug. 1?. 9 . A. M - -A light Rhockofan earthquake 



felt at Georgetown, which lasted about three 



seconds. The vibration apparently came from the 



north. Between this date and the' loth July there 



■ • four other light shocks, the 'bites of which are 



"i r< corded. 



Oet.21, 7|,P. M —A smart shock of an earthquake 



felt in San Francisco. The buildings situated 



over the water were violently shnken. There was 



h commotion in the water of the harbor a few 



minutes precedin? the shock, which caused several 



vessels to heave heavily at their hawsers and cables. 



Oct. 27, 3 P. M. — A light shock was felt in the 

 valley of Clear Lake. On the same day a shock was 

 felt in Downieville, which lasted about five seconds. 

 At Goodyear's Bar it was more severe than at the 

 preceding locality. 



Bee. 5, 11.20 A. M.— The shock of an earthquake 

 was felt at Humboldt Bay, which lasted about three 

 seconds. There were two vibrations, the last being 

 the most severe. 



Bee. 11,4 A. M — A shock was felt in San Fran- 

 cisco and at the Mission Dolores ; at the latter place 

 it is represented as having been quite severe. 



Jan. 2d, 1856, 10 A. M.— A light shock in San Fran- 

 cisco, which lasted about three seconds. The shock 

 came from the north and was undulatory. 



The whole number of which I have a record for 

 1855, amounts to twelve only; but there may be 

 others which have escaped my notice on account of 

 absence from the city. 



The following table will show the number of shocks 

 for each year, and eacli month of the year, for six 

 years from 1850 to 1855 inclusive : 



From the above it will be seen that of the total 

 number of shocks in six years in this state, forty- 

 eight have occurred during the spring, summer and 

 autumn months, and eleven during the winter months. 



Of the total number noted, twenty-seven have oc- 

 cured from San Luis Obispo south, and of the thirty- ' 

 two remaining, nine have been felt in San Francisco 

 at the same time they were observed at San Lais 

 Obispo, while the remaining twenty-three were felt at 

 San Francisco and north of that point. 



Notwithstanding we have had, what may, perhaps, 

 be considered a frequency in the recurrence of these 

 phenomena, still there are but a very few of the to- 

 tal number that would merit a moment's con- 

 sideration south of the twenty fifth parallel ofs 

 north latitude, for there they would be regarded a 

 minor affairs entirely. 



From all the facts in our possession relating to the 

 phenomena on our coast, it appears that the greatest 

 preponderance in action, and severity of effects, is 

 exerted for the most part, south of Point Conception. 

 for, from this place, east, south and north, to near 

 the I lolorado, the most conclusive e\ idences exist of 

 very recent volcanic action having been exerted on 

 rather an extensive scale, and is also still persist- 

 | ent in several localities within the area named, 

 though in a minor degree. 



It would be interesting to examine the changes of 

 level that have evidently taken place in this State 

 within the last five years; but. as more extended 

 observations would greatly assist us in forming 

 conclusions on this subiect. I will defer that portion 

 until a future day. 



