168 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
The following is a characteristic well log from the northern part of 
the central field: 
Log of well two blocks east of Lake Shore avenue, Los Angeles. 
[Elevation approximately 400 feet above sea level.] 
Thick¬ 
ness. 
Depth. 
Alternating blue clayey shale and fine soft sandstone. 
Feet. 
600 
Feet. 
600 
Same,- with oil seepages in sandstone. 
40 
640 
Blue clayey shale. 
60 
700 
Coarse oil sand. . 
70 
770 
Blue clayey shale, with sandy layers containing oil . 
180 
950 
Medium to coarse oil sand. 
50 
1,000 
Blue clayey shale. 
10+ 
1,010+ 
The following log is characteristic of the region about Second Street 
Park, immediately east of Lake Shore avenue, the well being two 
blocks southwest of that whose log has just been given: 
Log of well in Second Street Park, near Lake Shore avenue, Los Angeles, a 
[Elevation approximately 325 feet above sea level.] 
Sandy and clayey strata with thin strata of hard rock (“shells”) 
Oil sand interstratified with sandy clay... 
Tough clay (“putty”). 
Oil sand, with water. 
Sand with water. 
Thick¬ 
ness. 
Depth. 
Feet. 
Feet. 
650 
650 
125 
775 
200 
975 
3 
978 
“Watts, W. L., Bull. California State Miniig Bureau, No. 11, 1897, p. 6. 
West of Belmont avenue the dip becomes steeper, and although the 
water line becomes lower, and the wells consequently can go deeper, 
the field narrows appreciably. Between Burlington avenue and Alva¬ 
rado street the productive territory is about 600 feet wide; west of 
Alvarado street it narrows to 500 feet, and at the end of the field, 
near Coronado street, to about 300 feet. Near the corner of Belmont 
avenue and First street the wells penetrate soft fine sandstone and 
sandy and clayey shale for the first 850 feet, below which they pass 
into a 50-foot zone of clayey shale, in which are interbedded petrolif¬ 
erous sandy beds called 11 stray” sands by the drillers. The oil sand 
is struck at about 900 feet and is 100 feet thick, the dip here being 
between 30° and 40°. At 1,040 feet there is a 70-foot sand, which 
grades below into a white sand bearing salt water. This constitutes 
the lower limit of the productive zone. 
