GEOLOGY. 49 



from the surface, and was unable to pass through it. The fol- 

 lowing is a statement of the different strata encountered in the 

 Stockton well, and the thickness of each in feet, beginning at 

 the surface : 



Black loam, 6 ; red clay, 6 ; dark-red clay and sand, 18 ; blue 

 clay, mica, and sand, 10; blue clay, hard, highly stratified, 4; 

 blue clay, mica, and sand, 3 ; blue clay, hard, and highly strati- 

 fied, 4 ; green sandstone and clay, very hard, 29 ; blue clay, 

 sand, and gravel, slightly impregnated with gold, 2 ; blue clay, 

 sand, and gravel, 18 (100) ; green sandstone, clay, and mica, 

 hard, 15; fine gravel, 5; gray quicksand, 15; blue clay, 8; 

 gray sand and clay, 27; dark-blue clay and sand, 33 (203); 

 coarse gravel and pebble-stone, 27 ; blue clay, 7 ; gray sand, 

 13 ; blue clay and sand conglomerated, 12 ; light-gray sand, 3 ; 

 blue clay, 6 ; light sand, 9 ; blue clay, 1 ; fine gray sand, 12 ; 

 dark clay, 2 ; fine gray sand, 7 (302) ; clay and sand, 10 ; coarse 

 gray sand, 1; hght clay, 19; coarse sand, 14. (Note. — At 

 340 feet, in this stratum of sand, a red-wood stump was found, 

 and a stream of water ascended to within three feet of the 

 surface.) Light clay, 8; fine gray sand, li; light clay, r.O^ ; 

 coarse gray sand, 20 ; clay, very hard, 4 (400) ; gray sand and 

 clay, 5; clay, 20; coarse gray sand, 3; light clay, 15; line 

 gray sand, 4 ; light clay and sand, 1 ; coarse gray <.and and 

 clay, 1 ; light-blue clay, 11 ; gray sand and clay, 7; light blue 

 clay, 15; fine gravel, 1; light-blue clay and gravel, IP (496); 

 fine gravel, 25 ; clay and sand, 2 ; sand and clay, o : coarse 

 gray sand, 7 ; fine blue clay, 8 ; fine gray sand, 42. /'Fote.— 

 At 560 feet, in this stratum of sand, obtained a strean; of water, 

 rising five feet above the surface.) Gray sand and ciay, 15 

 (600) ; light clay and sand, 6 ; fine gray sand, 24 ; clay and 

 sand, 3 ; fine sand, 9 ; fine gravel, 3 ; fine gray sand, 5 ; coarse 

 sand, 2; blue clay and sand, 8; gray sand and clay, 8; ciay 

 and sand, 5 ; fine gray sand, 10 ; clay, 5 ; coarse gray sand, 2 ; 

 fine light-blue clay, 4 ; hard, chocolate-colored clay, 2 ; blue 

 day, 2 (698) ; fine gray sand, 30 ; clny and sand, 8 ; gray r^and, 

 4 ; light clay, 10 ; coarse sand, 6 ; blue clay, 4 ; dark clay, very 



