82 
OIL DISTRICTS OF SOUTHERN CALIFORNIA. 
be taken at about 35°. Southward from the axis the dip is compara¬ 
tively regular to a point beneath the summit of Oak Ridge. To the 
north, however, the dip continues but a short distance when it gives 
way to a southerly dip, the syncline thus formed being hardly less 
conspicuous than the anticline itself. 
The formations exposed in the Torrey anticline include, at the axis, 
a small outcrop of red and gray banded beds, believed to be the Sespe 
formation; overlying these is the principal formation of the field, heavy 
sandstone and chocolate-colored and gray-banded shales, which, by 
their fossils, have been identified as lower Miocene (Vaqueros), nearly 
1,000 feet thick; succeeding these, on the south the siliceous shale 
of the Modelo, which forms the crest of Oak Ridge opposite the Torrey 
field, and on the north—the siliceous member apparently being 
wanting—the heavy sandstone and conglomerate that are regarded 
as the Fernando. The Fernando is, however, of small extent in this 
vicinity, becoming prominent in the region of Tapo Canyon and 
attaining its maximum development several miles farther east, oppo¬ 
site Pico Canyon and beyond. 
A second anticline in the Torrey field lies in the lower slopes of the 
hills and is probably the west end of that believed to exist along the 
channel of Eureka Canyon, this, in turn, being continuous with the 
main Tapo anticline farther east. This fold may be seen to advan¬ 
tage in the west wall of Torrey Canyon, midway between its mouth 
and the forks half a mile up. East of this the flexure is not quite so 
pronounced and is, therefore, not so readily and perhaps not so correctly 
defined. Between Eureka and Torrey canyons the axis of the fold 
pitches to the west, while the strike of the beds is generally north and 
south. There is considerable doubt concerning the structure and the 
succession of the strata in Eureka Canyon. At first glance the regu¬ 
larity appears to be unbroken from the crest of Oak Ridge to the outer 
face of the lowermost foothills, the entire cross section, except at the 
summit of the ridge, presenting a southerly dip. From the region of 
Tapo Canyon, however, the main anticline may be traced with only 
slight irregularities to the divide between the Tapo drainage and that 
of Eureka Canyon, but at this point there is a sharp change in the 
position of the strata, as if the anticline had been severely compressed 
and the plane of its axis had been pushed northward with a dip of per¬ 
haps 60° to 90° to the south. (See PI. IV, sec. I-F.) In the higher 
portions of Eureka Ridge, a short distance north of this anticline, 
there is a syncline of secondary importance, which also lias probably 
suffered strong compression. The resultant position assumed by the 
beds thus influenced by the compound flexure described is one of 
southerly dip, with local obliteration of the axes of both folds, and an 
apparent continuous succession of strata from base to summit of the 
mountain. It is evident, however, that if this should prove to be the 
