FALL OF RAIN — ALTITUDES — EARTHQUAKES. 19 



which is only produced so long as the wind is north. Along shore, from Point Concepcion 

 south, where the level plains are sheltered by the mountains from this wind, the winter months 

 are a genial, pleasant season, during which vegetation is growing rapidly, and the only dis- 

 tinctions of the year are a wet and a dry season. During the rainy season, ploughing, planting, 

 and all the operations of spring, are carried on. The whole of the rain of this period not falling 

 at once, but at intervals, like " the former and the latter rain" of Judea, allow of the opera- 

 tions of the field being carried on with advantage during the interval of the rain fall. 



The annual fall of rain in the central counties is about twenty inches. In the south 

 it ranges from ten to twelve inches ; as this quantity does not suffice to keep rivers running 

 throughout the year, or to soak the soil thoroughly with moisture, irrigation is necessary during 

 the early summer months. In the later periods of the year everything languishes for drought, 

 and the valleys which blossomed like the rose in March and April with every wild flower, rare, 

 beautiful, or fragrant, becomes, from July till October, brown, parched, fissured, and the abode 

 of the grasshopper and the reptile. During October, sooner or later with the latitude, comes 

 the first rain, and vegetable nature starts again into life and variety. 



The coast nxountains have some lofty peaks in their course north of San Francisco, but the 

 chains are short and ill defined. South of that city, or from latitude 38°, they extend south 

 through 4° of latitude until the eastern ranges become blended with the Sierra Nevada, and the 

 western ones run out along shore, and reappear in the islands Santa Rosa, San Miguel, Cle- 

 mente, Anacapa, with the minor islets. As many as four chains of the range run for some 

 miles parallel, and, being remarkably continuous, they have but few breaks or passes ; so that 

 they form a perfect barrier, allowing none of the inland waters (save one, the Santa Maria) to 

 escape by any other outlet than the northern termination of the ranges. Hence it is that San 

 Francisco bay becomes the receptacle of so much of the river waters of the south. These chains, 

 however, contain no such high mountains as the northern ones, and but two such elevations, as 

 Mount Ripley, which is 7,500, or Mount Hood, 8,000. These are San Emilio, which approaches 

 9,000 feet, and the high mountain west of it, in the Santa Lucia hills, which is almost 10,000 

 feet high. 



Southern California is remarkably subject to earthquakes. In the counties of Santa Barbara, 

 Los Angeles, and San Diego, they are felt several times in the year ; within the last six years 

 the ascertained number felt amounted to fifty-nine, or more than nine shocks a year. There 

 is thus convincing evidence that plutonic forces are not quiescent there ; other proofs, however, 

 exist in the but recently extinguished fires of the northern volcanoes, and the still open fissures 

 in the southern chain, whence steam acid vapors, and even flame, yet occasionally escape. 

 These forces, still in activity, have elevated the Cortes rocks, in 1853, as the result of a sub- 

 marine volcanic action, whose total efiect has been to elevate the coast mountains to their 

 present level. Such an upheaval is never produced by a single eff'ort, but by several successive 

 elevatory actions, with long intervals of rest between, during which the incumbent but com- 

 paratively shallow waters flowed over the surface with a gentle current motion, and formed the 

 deposits of sand and gravel, and produced the ancient terraced flats so numerous over the 

 whole State. 



The elevation of the Coast Range above the water level was an event much later in time than 

 that of the Sierra Nevada. During the Eocene period the latter range must have had its crest 

 considerably above water, and was uplifted, finally, after the Miocene period ; but it is probable 

 that during the whole of the Miocene period the Coast Range was altogether beneath the sea 



