LOS ANGELES DISTRICT : EASTERN FIELD. 
163 
STRUCTURE. 
PI. XX, sec. G-H, illustrates the probable relations of the beds in 
the eastern part of the eastern field. The contour lines a in PI. XIX, 
showing the distance of the upper oil sand below the Los Angeles 
city datum (255 feet above sea level), also help to make clear the 
structural features of this district. As would be expected in a region 
where two important flexures come together at an acute angle, the 
structure is complex. The flexures referred to are the Elysian Park 
anticline, which trends N. 60° W., and the anticline and fault along 
the north side of the oil field, which trend in an approximately east- 
west direction. As the beds of sandstone and shale in the Elysian 
Park anticline approach the east-west line of disturbance, they tend 
to deviate so that their strike is more nearly east and west. Simi¬ 
larly, the beds following the line of the east-west disturbance are 
inclined to turn so that their trend is somewhat north of west as they 
approach the thick beds of the Elysian Park anticline. This tend¬ 
ency to change in strike occurs not only in the beds at the surface, 
but also in the oil sands, as is shown by the contours in PI. XIX. 
The structure in the major part of the eastern field is irregular, the 
average dip, however, being less than that of the central field. The 
inclination of the strata appears to be most regular just east of the 
Sisters’ Hospital. From this point almost to Bernardo and Yale 
streets the dip becomes less and less, but near the latter point it 
increases abruptly to 50° or more. Toward the east the beds are 
very much disturbed. Near the corner of Ramona avenue and Col¬ 
lege street the dip is about 35°. Immediately south of this point is 
a line of fracture, on the south side of which the strata dip 45°. 
The conditions beyond the east end of the field are not known 
because of the lack of surface outcrops and well logs. 
The line of disturbance which begins west of Sunset boulevard, 
northwest of the Sisters’ Hospital, and extends almost in a straight 
line to the corner of Bernardo and Adobe streets, appears to be a 
very sharp anticline bounded on the north by a fault in which the 
downthrow is on the south side. In a small cut on the west side of 
Sunset boulevard, in the axis of this zone of disturbance, the beds 
dip from 80° N. to 80° S. This has the appearance of an overturn. 
However, dips obtained in the subway between the Sisters’ Hospital 
and the boiler house and immediately north of the latter show an 
anticline with dips ranging from 45° S. through horizontal to 45° N. 
A similar northerly dip is found northeast of the hospital on the 
corner of Beaudry avenue and the alley between Beaudry and Hin¬ 
ton avenues. These dips occur in thinly laminated yellow sandstone 
a The lines showing the position of the oil sand in the central and eastern fields tire copied from W. L. 
Watts's map of this field, given in Bull. California State Mining Bureau, No. 19, 1900, fig. D. 
