82 
SANTA MARTA OIL DISTRICT, CALIFORNIA. 
to an anticlinal axis and is the line mapped. In places it is a true 
anticline, completed by beds of gentle dip that form a broad syn¬ 
cline of the platform on its southwest side. South of Corralillos 
Creek the structure curves westward and the Schumann anticline is 
sharply defined and overturned. It is seemingly to be correlated 
with a large anticline exposed in the Tejon-Vaqueros rocks on the 
coast north of Point Sal. South of Waldorf this anticline, as shown 
by the dotted line on the map, is not certainly continuous, but west 
and south of Schumann the same or a similar fold becomes well 
developed and the strata dip away from it on both sides. In this 
portion and southeast of Schumann Canyon its summit is broad, 
but the dips become very steep farther out on its northeastern 
flank. It plunges to the southeast and finally dies out. 
Asphalt and other surface indications of oil, such as burnt shale 
and bituminous shale, occur at many places in the Casmalia Hills. 
The shale is especially bituminous along and near its contact 
with the Fernando on the northeastern side of that part of the hills 
which lies north of Schumann, and it has been burnt in a number of 
places in the same region. Outcrops of burnt shale are prominent 
on the hill just southeast of Schumann, and near the contact at the 
northern base of this hill the shale is extremely bituminous. Wells 
put down in the region about Schumann encounter heavy tar at 
depths below 2,000 feet, but no paying wells have been struck. It 
seems likely, however, that at greater depths, possibly 3,000 feet or 
so, the horizon of the productive flinty beds encountered in the 
Graciosa Ridge wells will be penetrated and will yield lighter oil in 
paying quantities. 
The region lying north of Schumann Canyon, west of the valley 
that runs southward out of the hills and opens to Schumann Canyon 
1 mile N. 45° W. of the Casmalia depot, and west of the road that 
crosses the ridge to Waldorf will probably not yield any large quan¬ 
tity of petroleum, because the strata are so low in the formation 
and because there appear to be no sufficiently well-developed folds 
to afford good points of accumulation. Oil might be found in small 
quantities in the minor folds between the lower portion of Schumann 
Canyon and the fault. The shale along the coast here is very bitu¬ 
minous. East and south of the supposedly unproductive region 
outlined above the plunging structure exposes higher portions of the 
Monterey shale and the conditions warrant the conclusion that oil 
can probably be obtained in the neighborhood of the major anti¬ 
cline. Southeast of the point where the road south of Waldorf 
crosses the ridge the territory appears promising, especially along 
the anticline and on its east side. The oil which is supposed to rise 
on the steep eastern flank of the fold probably does not reach far 
under the broad western flank. South of Schumann, where the fold 
