29 



which agitated the country prior to that time, and that the recession of the sea 

 from those points has been gradual; an idea which is borne out most fully by 

 corroborating evidences in other and more distant parts of the State. 



PLAINS OF LOS ANGELES. 



In the preceding pages we have given a brief summary of the general char 

 acteristics relating to the geology of a portion of the coast and San Bernardino 

 mountains. We shall now proceed to examine the probable positions which the 

 sedimentary rocks of the latter chain occupy beneath the surface of these plains. 

 From what has been said of the positions of the rocks among the foot-hills 

 skirting the northern edge of the valleys, it will be seen that it is with the lat 

 ter or infusorial group that we have to work in forming conclusions respecting 

 the structure of these plains below the surface. The great extent of these 

 plains requires more than a passing notice, and their value can only be appre 

 ciated by a careful examination of all their characteristics both below as well 

 as on the surface. We cannot judge of the value of a district of country by a 

 superficial glance at its exterior features, and nothing but a searching and dis 

 criminating view of its hidden resources can give us an adequate idea of either 

 its present worth or its prospective facilities. This remark will apply with great 

 force equally to the Plains of Los Angeles, the Valley of the Sacramento and 

 the lands bordering it, as well as to the broad district embraced in the valleys 

 of the San Joaquin and Salinas Rivers, especially when we come to consider 

 their agricultural fitness, or their application to any pastural purposes. It is 

 needless here to dilate upon the importance of a knowledge of the geological 

 structure and mineral affinities which often influence the virtues of soils render 

 ing them more or less adapted to certain purposes of an agricultural character. 

 Great error might doubtless arise in many instances were we to attempt a judg 

 ment of some of the districts alluded to, without such knowledge; for instance, 

 a stranger passing along portions of the Plains of Los Angeles in our long dry 

 summer season would find the beds of streams dry, the herbage and vegetable 

 growths seared, the earth parched and cracked open as it lies baked in the burn 

 ing heat of the sun, the timber sparce and of a gnarled and almost useless des 

 cription; upon these external appearances he would conclude with great error 

 that he had found a region unfit for the habitation of man, when in truth, 

 such is the sub-structure of these plains that their soils are unsurpassed in fertil 

 ity by any others in the United States, as the returning seasons of rain would 

 prove to the same traveler, when he should find himself almost buried in the 

 luxuriant growth of the grasses, wild grain and herbs of these districts. And 

 it ought to be observed that vast portions of these lands may be irrigated, so that 

 even in the summer they can be brought within the profitable control of the 

 husbandman. 



These portions of the country which are not found to yield the precious metal, 

 or any other useful mineral products to any great extent, can be interesting in 

 an economical point of view only with reference to their means of agricultural 

 occupation. It will be with the purpose of precluding erroneous conclusions 

 from being drawn out of any remarks we may make in this connection, that we 

 propose at this time to consider the geological structure of these sections in the 

 bearing it may have upon the prospective interests alluded to, interests which 

 we think are destined sooner or later to test all the capabilities of these valleys 

 for agricultural and horticultural production. 



The first question in importance to be settled on this subject is the one of 



