186 • TRANSACTIONS OF THE 



of two kinds of land — the red soil of the higher lands, and the light, 

 chocolate-tinted loam of the valleys. Only the subsoil of the first has 

 thus far been analyzed, and suffices to show the general character of 

 the lands. The surface soil of the red land to the depth of twelve to 

 thirteen inches, is relatively light, so that dry lumps can be readily 

 crushed between the fingers — an easily tilled loam. The subsoil, 

 thirteen to twenty-five inches, is a good deal heavier; the lump not 

 to be crushed between the fingers, and quite adhesive when wetted. 

 This subsoil varies in thickness; from a depth ranging from about 

 thirty-three to fifty-five inches the red soil changes to a yellowish 

 tint; then immediately upon the bedrock, which lies at variable 

 depths, the color is bluish. The bedrock is slate traversed by ledges 

 of "round, very heavy rock." Ninety-five per cent of the subsoil 

 passes the sieve of 1-50 inch meshes, and the analysis of the fine earth 

 gave the following result: 



Red Subsoil, Ione. 

 Insoluble matter 48.98 



Soluble silica , 18.70 J ^^'^^ 



Potash .22 



Soda .10 



Lime 2.77 



Magnesia 1.80 



Br. oxide of manganese .09 



Peroxide of iron 7.91 



Alumina 14.98 



Phosphoric acid .04 



Sulphuric acid i .06 



Water and organic matter 4.11 



Total 99.76 



Humus in surface soil .607 



Available inorganic .567 



Hygroscopic moisture 7.09 



Absorbed at 10.5° C. 



The percentages of potash and phosphoric acid in this subsoil are 

 quite low for California, the latter ingredient being rather deficient. 

 Doubtless the analysis of the surface soil would have given higher 

 percentages of both; but the high figure for lime off'sets in a measure 

 the defect, in rendering the other ingredients active. While the soil 

 would not endure long without fertilizers under grain culture, it is 

 certainly well adapted for fruit, and whenever production shall 

 become stinted, phosphate fertilizers will first be needed. High 

 quality rather than quantity is to be expected from this land. 



The chocolate-colored valley soil is doubtless richer in plant food, 

 and would probably answer excellently well for apricots and pears, 

 while the red land is more especially adapted to vines, almonds, 

 IDcaches, and olives. 



No. 643. — Black waxy adobe, from the Colton ranch, at the foot of 

 Mt. Diablo, on the Alamo road. This is an adobe soil of the most 

 extreme character thus far met with. It bears a growth of fine white 

 oaks, in rare places large sunflowers, but little or no grass. When 

 dry it is of a dark slate color, and of stony hardness. When wet it 

 is as adhesive as birdlime, and vehicles running on it soon have 

 their tires thickly covered with a firmly adhering, uneven ring of 

 adobe, which must be from time to time removed by means of a cut- 

 ting tool, in order to ease the team and occupants. Like the other 

 adobe soils, it "slakes" quickly on wetting the stony, hard, dry 



