8 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
LOWER ZONE. 
Fig. 2 is a section of the lower 400 feet, which forms a persistent 
divisional zone between the Topatopa formation and the main mass 
of red beds. This part of the formation occurs at the mouth of a small 
tributary entering Sespe Creek from the slopes of Sulphur Peak at a 
point about a mile above the mouth of Tar Creek. It reappears 2 or 
3 miles lower down Sespe Creek, in the heart of the Coldwater anti¬ 
cline. The distinguishing features of this zone are the whiteness of 
its sandstones, in contrast with the measures both above and below, 
and the delicate green and pink tints which pervade its clays and 
Fig. 2. —East-west section across Sespe Canyon above mouth, of-Tar Creek, showing detail of the 
lower portion of the Sespe formation, together with its oil-bearing sands. 
shales. The heaviest of the sandstones is a bed about 80 feet thick 
at the base. The lower half of the zone has produced oil in com¬ 
mercial quantities. 
RED BEDS. 
GENERAL DESCRIPTION. 
The beds of brownish-red color which constitute the mass of the 
Sespe formation and overlie the lower zone present at their base a 
band of coarse conglomerate from 40 to 100 feet thick. Above this is 
300 or 400 feet of massive sandstone, with pebbles here and there. 
This is overlain by approximately 500 feet of heavy sandstone, with 
