92 
SANTA MARIA OIL DISTRICT, CALIFORNIA. 
DETAILS OF TIIE DEVELOPED TERRITORY. 
DEFINITION OF FIELDS. 
In the following paragraphs are discussed the more important 
details regarding the structure, geology, oil zones, oil, and production 
in the areas in which development is well under way. These areas 
within the Lompoc and Guadalupe quadrangles fall naturally into 
two fields—the Santa Maria field and the Lompoc field. The former 
covers the whole territorv between the Los Alamos and Santa Maria 
valleys, and the latter is used to designate the region south of the Los 
Alamos Valley. A third, the Arroyo Grande field, covering the ter¬ 
ritory north and northwest of the town of that name in San Luis 
Obispo County, lies to the north of the region mapped, but is briefly 
discussed. A note on the Huasna field, east of Arroyo Grande, is 
also appended. 
SANTA MARIA FIELD. 
CONTOUR MAP. 
WHAT IT SHOWS. 
The contour map of the Santa Maria field (PI. X) shows the bound¬ 
aries of the different properties, the approximate location of all the 
wells, and the general structure of the field. The structure is indi¬ 
cated by contours showing the distance below sea level of a hypo¬ 
thetical horizon, zone, or bed, which just reaches sea level at the 
highest part of the axis of the Mount Solomon anticline. The con¬ 
tour interval is 100 feet. By means of this map the direction and 
amount of dip of the strata in the oil-bearing Monterey shale may be 
calculated for any point in the field, as the contour lines show the 
direction of strike (to which the dip is at right angles), and the hori¬ 
zontal distance between any two contours is the distance through 
which the beds dip 100 feet at that particular point. 
BASIS OF. CONTOUR MAP 
The property lines were sketched from a map kindly furnished by 
Frank M. Anderson. The wells were located in the field bv the eve, 
supplemented by pacing and in some instances by information fur¬ 
nished by the managers of properties. The log of every well in the 
area either finished or down any considerable distance in August, 
1906, was used in the determination of the structure and the com¬ 
pilation of the data concerning the oil zones. All additional informa¬ 
tion available up to January 15, 1907, has been used in a revision of 
the contouring. All of the obtainable surface evidence of dip and 
strike of the beds was also used in the preparation of the map. In 
every case where the surface and well-log evidence were at variance 
