30 



[APPENDIX 



reach, the depth of 775 feet at the City of Sacramento, in order to obtain 

 a permanent supply of water. 



This presumytion is based upon the fact that a constant source does 

 not exist above the conglomerate, and this point is selected more for the 

 purpose of exhibiting the greatest probable depth at which a permanent 

 supply of water wiuld be found ; the probabilities of obtaining water at 

 much less depths is strong, and amounts to almost a certainty, that water 

 would be found immediately below the sandstone, and above the first 

 slates ; in that case the depth would be diminished about two hundred 

 and fifty feet. 



If a correct idea of the inclination of the sedimentary rocks is pre 

 sented in the diagram, we shall have the following depths at different 

 distances from the centre of the basin, on both sides. 



ON THE WEST SIDE OF TPIE RIVER, j ON THE EAST SIDE OF THE RIVER. 



11 miles, 700 feet. 



15 " 650 " 



22 " ..550 " 



Sacramento City, 775 feet. 



12 miles, 700 " 



17 " 650 " 



20 " ..625 " 



At the distance of twenty miles the rolling hills are entered in which 

 springs usually abound. 



The rocks on both sides of the valley are arranged in the order in 

 which they occur, as observed by the outcrop. 



Sandstone, 



EOCENE, 



Fosil Sandstone, 



Trap, 



Granite, 



Sandstones and upper Slates, 

 Conglomerate, EOCENE. 

 Lower clay Slates. 

 Granite. 



These rocks included within the Eocene lines are classed by Mr. Dana, 

 as the early sandstone, slates, and conglomerates, to distinguish them 

 from the more recent tertiaries among the Coast Mountains. 



The geological structure of this basin was noticed by Mr. Tyson in 

 1849. He examined it with a view to ascertain whether a deposit of 

 coal might not exist below the surface; and also whether its structure 

 would indicate the means of supplying water for agricultural and me 

 chanical purposes. 



In regard to the first question he says : " The first query is answered 

 by the fact of finding the comparatively recent strata of a formation, not 

 older tjaan the eocene and miocene periods, resting immediately on the met- 

 amorphic or hypogene rocks of ancient origin, the remaining members 

 with all the sedimentary rocks of older date being entirely wanting, 

 and the the coal formation, which belongs to the lower of the second 

 ary series." A coal formation under the basin is therefore out of the 



