76 
GEOLOGY. 
The roadway over these hills was lined with clumps of the prickly pear, rising to the height 
of from two to five or ten feet, and hearing fruit which was exceedingly abundant and in full 
perfection. When perfectly ripe it has a beautiful claret color, with a shade of purple, and is 
very refreshing to the traveller if suffering from thirst. It is, however, a difficult operation to 
pick and prepare them for eating without having the hands filled with the sharp prickles. The 
best way to pick them is to insert a pointed stick at the end, and then cut them loose from the 
plant with a long knife. They are then securely held by the stick while the skin is cut off. 
View of the Pacific ocean. —In descending from the higher parts of the range, the eye was 
permitted to wander over an extended area sloping gently away from the mountains towards the 
west. This is one of the most marked peculiarities of the landscape on the western coast; 
every mountain and mountain range is flanked by long, gently descending slopes, which seem 
like plains when passing over them, but viewed from a distance their inclination is strikingly 
evident. In the present instance the slopes appeared to be prolonged in a limitless plain ex¬ 
tending to the horizon ; but a more favorable point of view showed to us the broad, mirror-like 
surface of the great ocean. 
LOS ANGELES. 1 
Our approach to Los Angeles was over a portion of the slope just described, and we reached 
the city in the evening of the 31st October. It is on the Los Angeles river, and is about twenty 
miles distant from the Pacific, where its port, (or embarcadero,) San Pedro, is situated on an 
open bay at the mouth of the San Gabriel and Los Angeles rivers. 
Before reaching the city, and about five miles northwest of it, we crossed a small brook with 
vertical banks, in which the edges of nearly horizontal strata were exposed. They consist of 
light-colored shales, thinly stratified, and charged with bitumen, which formed black and brown 
seams between the layers. A coarse conglomerate, composed of sandstone, boulders, and 
masses of shale, was superimposed on these strata, and looked like ordinary beach-shingle. 
Nearer the city, an excavation had been made in the side of a hill into horizontal strata, which 
were white and chalk-like. They were compact; and large masses of the white rock could be 
readily broken out, it being very friable and light, yet possessing great tenacity and toughness. 
This rock is principally siliceous, and does not effervesce with acids. It is underlaid by sand¬ 
stone, also nearly white. No fossils were found ; but the strata are like those afterwards seen 
at Monterey, and are probably Miocene Tertiary. 
Bitumen Springs— u Tar Springs .”—There are several places in the vicinity of the city where 
bitumen, or mineral pitch, rises from the ground in large quantities. These 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 out on all sides, so that it 
covered a circular space about thirty feet in diameter. The accumulated bitumen had hardened 
by exposure, and its outer portions were mingled with sand, so that it was not easy to deter¬ 
mine its precise limits. It formed a smooth, hard surface like a pavement; but towards the 
centre it was quite soft and semi-fluid, like melted pitch. The central portion of the overflow 
was higher than the margin ; and it was evident that all the hard, portion had risen in a fluid 
1 The Pueblo de Nuestra' Sefiora la Regna de los Angeles was founded at the end of December, 1781, by order of the 
governor of California, Don Felipe de Neve. 
