57 



Much of the water which flows in the Sacramento as it approaches the Bay 

 of Suisan is derived from drainage through and between the superficial strata of 

 the plains, or from the small subterranean courses which flow out over the mid 

 dle clay beds, which form the substratum of the sandy and gravelly clays above. 

 One of the best proofs which is presented, of the existence of these latent cur 

 rents along the plains from the Tipper Sacramento, as far down as Yolo County 

 on the south, is found in the fact that there is derived a constant supply to the 

 large lagoons of the plains, which we can trace to no other source, thus driving us 

 to the conclusion which the known formations of the valley corroborate. Another 

 fact is worthy of attention in connection with this subject, which is that these 

 lagoons have outlets which distribute their waters over the tule grounds, where 

 they maintain quite uniform stages during the summer months, which is traceable \ 

 to no other known and visible system of supply, and compels us again to the belief l 

 that the subterranean courses of the lost mountain streams must furnish its 

 elements. If the lagoons were filled merely by the overflow of the plain during 

 the rainy season, they would not maintain their uniform height throughout the 

 dry season as they now do, and they would furthermore necessarily exhibit all 

 the features of mere standing pools of stagnant water, no signs of which is now 

 to be seen about any of these bodies of clear water west of the Sacramento. 

 It has been asserted, though I have no personal knowledge of such a fact, that 

 a light current is at times perceptible to the south, in some of the larger lakes. 



The water in many of these lakes is of considerable depth, perfectly clear, and 

 much colder than the waters in the rivers, their dimensions varying from eight 

 to twelve miles in length, and three to five miles in breadth. The existence of 

 these bodies of water and their number, temperature, and their uniform depth 

 and volume teach us plainly that the source of their supply must be traced to 

 some other cause than that of the mere periodical overflow of the surrounding 

 lands. If this be admitted, we must look for that supply to the more elevated 

 borders of the valley on the east and west, or at their northern extremities. 

 A sufficient supply of water is not to be found on any part of the west border 

 of the plains, to produce these lagoons until after we pass the Cottonwood and 

 Clear Creeks to the north, and we cannot, therefore, look to that direction 

 alone; but we find the apparent source of an ample supply in the numerous 

 streams that sink upon the upper and eastern sides of the valley which, as 

 before stated, hide the greater portion of their contents before reaching the 

 main channels through which they conduct their discharge in the rainy season. 

 An additional evidence that the waters of these streams pass beneath the sur 

 face, and in a certain degree are superficial, is a fact that heavy forest growths 

 frequent different levels, and in their distribution are found at distances of miles 

 from any currents of water which would be at all adequate to the support 

 of such forests, by imparting to the soil in which they grow the necessary 

 moisture for their nutriment. 



The structure of the plains below the surface, has been inferred from an exami 

 nation of the changes which take place in the soils which are met with in traveling 

 from the higher terraces of the northern end to those of the more southerly levels, 

 which latter are but a few feet above tide water, and in the position of the clay 

 beds which are found lying upon the first outcrop of the slates which are found in 

 the lower foot-hills before entering the more elevated mountain districts. A verti 

 cal section of the country spoken of, would give a depth of about four hundred feet 

 as the superficial covering of the valley where it is exposed to view. The various 

 depths of the principal groups of this part of the State will be found in the table in 

 the following pages, and the respective positions from the surface, as demonstrated 

 by the boring of the Stockton well, which has perforated them to the above noted 

 depth of four hundred feet. The thickness of the lower clay bed is, of course, 



8 



