LOS ANGELES DISTRICT: PREVIOUS REPORTS. 139 
general were carried on until 1894, when W. L. Watts began a study 
of the petroleum deposits for the California State mining bureau. 
Blake was the pioneer geologist in this region and his observations® 
are wonderfully accurate in view of the difficulties under which he and 
his associates worked. The part of his report relating to the southern 
California oil fields is that describing the region of the route traveled by 
his party, from San Francisquito Pass, north of Saugus, southward 
through Fernando Pass to Los Angeles and thence eastward to San 
Bernardino. He describes the east end of the Santa Susana Moun¬ 
tains, mentions Tertiary fossils found in Fernando Pass, and speaks 
of the eruptive rock (basalt) which outcrops in Cahuenga Pass. 
About 5 miles northwest of Los Angeles he found some “ light-colored 
shales, thinly stratified, and charged with bitumen, which formed 
black and brown seams between the layers/’ b and correlated them 
with the Miocene shale found in the vicinity of Monterey. Blake’s 
only observations bearing directly on the oil question refer to the 
bitumen which lie noticed exuding from the light-colored shale, and 
are as follows: c 
Those places are known as tar springs, or pitch springs, and some of them form large 
ponds or lakes. One of the springs was passed on our way to the city, and was near the 
outcrop of bituminous shale in the banks of the creek already described. This spring 
was nothing more than an overflow of the bitumen from a small aperture in the ground, 
around which it had spread on all sides, so that it covered a circular space about 30 feet 
in diameter. The accumulated bitumen had hardened by exposure and its outer por¬ 
tions were mingled with sand, so that it was not easy to determine its precise limits. It. 
formed a smooth hard surface like a pavement, but toward the center it was quite soft 
and semifluid, like melted pitch. The central portion of the overflow was higher 
than its margin; and it was evident that all the hard portion had risen in a fluid state 
and by the heat of the sun had been gradually spread out over the surface; at the same 
time being constantly exposed to dust, it had become so thoroughly incorporated with it 
that the compound had all the consistency of an artificial mixture. Tufts of “salt 
grass” were growing in some of the hollows and crevices of the outer portions of the 
hardened bitumen. 
During the winter of 1854-55 an exploring party under the direc¬ 
tion of Lieut. John G. Parke, accompanied by Dr. Thomas Antisell, 
geologist, examined the Santa Susana and Santa Monica ranges and 
the region adjacent to them as far east as San Bernardino. The results 
of this examination are set forth in Parke’s report, 0 one chapter 
dealing with the geology of the two and another with the plains of 
San Fernando, Los Angeles, and San Bernardino. By far the most 
interesting chapter bearing on the oil question in Antisell’s report is 
that on “ Bituminous effusions,” which gives a brief summary of all 
the then known bitumen deposits in the State. The following notes 
concerning the Los Angeles region are copied from this chapter : d 
a Pacific Railroad Report, vol. f>, pt. 2, 1850, pp. 65-88. 
b Op. cit., p. 70. 
c Pacific Railroad Report., vol. 7, pt. 2, 1857, pp. 75-86. 
dOp. cit., pp. 112-113. 
