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SANTA MARIA OIL DISTRICT, CALIFORNIA. 
GEOLOGY. 
GENERAL STATEMENT. 
All the productive wells in the Lompoc field start in the Fernando 
formation and penetrate its clays, sandstones, and conglomerates 
for distances ranging from 45 to 800 feet. The great variation in the 
thickness of the Fernando in adjacent wells (the beds over much of 
the territory being nearly horizontal, implies great inequalities in the 
surface of the underlying Monterey shale, and this in turn signifies a 
profound unconformity between the two formations. Water is 
encountered in the Fernando at various depths in the different wells. 
From the base of the Fernando to the top of the oil sand the wells 
pass through shale (largely “brown,” according to the logs). Hard 
siliceous “shell ” layers are encountered here and there in this shale, 
and in one well hard limy “shells” were struck at only 1,180 feet 
from, the surface. These limy layers are abundant in the formation 
just above the oil zone, but are not found in most of the wells above 
this horizon. 
Oil and gas are found in minor quantities in the shale at various 
depths, from 500 feet down in some of the wells in the northern part 
of the developed area, although such occurrences are not recorded for 
the wells in the southern part. 
BURNT SHALE. 
One of the most interesting features of the geology of the Monterey 
shale in this area is the evidence that combustion has taken place 
within it at certain points about 1,000 feet below the surface. Mr. 
Orcutt, of the Union Oil Company, exhibited samples of red shale 
coming from depths of 950 and 1,040 feet below the surface in Hill 
well No. 1, which are identical in appearance and texture to the burnt 
shale found so abundantly in the bituminous areas of the Monterey 
on the north side of the Santa Maria field and in other fields through¬ 
out the State. Traces of petroleum were associated with the upper 
stratum of burnt shale in Hill well No. 1. 
OIL ZONES. 
The principal productive oil zone in the Lompoc field is struck at 
depths below the surface ranging from about 2,200 to more than 
4,100 feet. In nearly all the wells-the productive strata are overlain 
by a more or less prominent series of limy “shell ” layers, which appar¬ 
ently act as barriers to the upward migration of the oil at the present 
time. The beds beneath these limy “shells” are true sands in most 
places, although in some of the wells these sands are interstratified 
with varying quantities of shale and limestone “shells.” The thick¬ 
ness of the oil zone varies from about 160 to 700 feet, and a productive 
series of sands, shales, and “shells” is said to be penetrated for a 
