112 
ASPHALTUM OF LOS ANGELES VALLEY. 
point is limited, appearing to be tbe commencement of a series of outflows which are found 
occurring at intervals eastward beyond the Los Angeles river ; with this deposit may be 
classed— 
8 and 9. The deposits on the Santa Clara river tributaries and among the Susanna hills .—These 
are but the eastward continuation of the foregoing outflow. If a line be drawn from the deposit 
upon the banks of the Buenaventura river in a southeast direction it will touch in its course 
several disturbed districts containing deposits of bitumen, until it reaches the low hills north of 
the Pueblo Los Augeles, where the largest overflow has occurred. The small stream which 
rises in the low ranges between the Buenaventura and Santa Clara rivers, and finds its way 
down to the latter stream, about 12 miles up its valley, received the provisional name of Tar 
creek, from its passing through a small valley in which several very extensive outpourings of 
the bitumen were observed. Several small wells or springs were found here delivering small 
quantities which had consolidated further down on the slope. The bitumen occasionally pours 
into the creek, and is washed down into the Santa Clara river. It was detected here at the 
point of debouche by the main party travelling up the Santa Clara, and observed by Mr. Camp¬ 
bell along the line of the creek in a cross trail made by him from Matilihah to the Santa Clara 
river. From these deposits occurring in a rocky district troublesome to reach they are not 
available sources of bitumen. They occur in the brown sandstones last described. Deposit No. 
8 has already been alluded to as most distant from the shore. 
A deposit occurs on the Santa Clara river, about 8 miles up the valley; it occurs in one of 
the ranges of the Sierra Susanna, is in close proximity to whitish amygdaloid trachyte, met 
with in brown sandstones accompanied by a sulphur spring, and is on the right bank of the 
river. Report speaks of other deposits occurring more easterly along the chain of hills which 
run toward the Cordilleras. 
10. Deposit of Los Angeles valley .—This occurs between one and two miles north of the 
pueblo in an air-line, but as the low range of the Sierra Monica, in which it is found, runs east 
and west, the road winds round northwards to reach it. These hills are a brownish yellow 
sandstone, 120 feet thick, passing into a hard shale lower down, which is covered up by a bed 
of soft white argillite, 20 feet thick, in turn covered up by a thin brownish fissile slate, 30 feet 
thick; above all is a capping of porphyry and granitoid drift gravel. The strata are tilted at 
a high angle dipping northwest from 40° to 75° ; upon their upturned edges the drift rests. 
Whitish trachyte and greenstone are the upheaving rocks which run north 60° west, and alter 
the sandstones in contact, rendering them hard, sonorous, and giving them a line of cleavage 
nearly vertical to the plane of deposition. The asphalt is protruded through these strata near 
its contact with the argillite, forming distinct wells or springs, which overflow. The land 
where they lie is owned by Captain Dryden, who, at the time of visit, was sinking a pumping 
apparatus for hoisting up the bitumen, which is very liquid at this locality, where it forms a 
small pond a fourth of a mile in circumference, thinner in the centre than at the edges. Like 
the other varieties, it readily dries, and forms a solid pavement some yards around the edge of 
the wells. A large quantity is occasionally raised and sold at the rate of 40 gallons for $5 == 
$1 for 8 gallons. It is in some demand for flooring and roofing. The quantity drawn at 
present seems to have no effect in diminishing the supply; but as intervals of rest occur, owing 
to the limited demand, it is difficult to say what continuous supply could be derived from this 
source. Mr. Trask, in his report, (Doc. No. 14, Calif., session 1855,) calculates the amount 
of asphaltum in the counties Santa Barbara and Los Angeles as not less than 4,000 tons. As 
