CHAPTER VI. 
TEJON TO THE GREAT BASIN AND PASS OF SAN FRANCISQUITO-- 
PASS OF SAN FRANCISQUITO TO THE MOJAVE RIVER. 
TEJON pass.—GRANITIC AND METAMORPHIC ROCKS.—SLOPE OF THE BASIN.— YUCCA TREES.—TERTIARY.—LOST MOUNTAINS.— 
SPRING. 一 PoRPHTRY. 一 SPRING RESORTED TO BY INDIANS.—HORNS OF THE MOUNTAIN SHEEP.—DRY LAKE-BED OF CLAY.— 
GRANITE FORMING LOST MOUNTAINS.—TRANSVERSE CHAIN OF MOUNTAINS FORMING THE SOUTHERN BOUNDARY OF THE 
SLATES—GOLD.—SAN FRANCISQUITO PASS TO THE MOJAVE RIVER.—Cow CAMP—HORNBLENDE AND MICA sLATE.—HILLs 
OF HORIZONTAL STRATA.—FERTILE VALLEYS.—SLOPE OF THE GREAT BASIN.—PLANTS.—MOJAYE RIvER.—GRANITIC AND 
METAMORPHIC ROCKS.—ÄLLUVIUM. 
TEJON TO THE GREAT BASIN AND THE PASS OF SAN FRANCISQUITO. 
On the 10th of October I accompanied Lieutenant Williamson on his trip through the Great 
Basin towards the Mojave river. The wagons and the main body of the Expedition had been 
sent forward by. way of the Canada de las Uvas, and were to wait in one of the grassy valleys 
near the Pass o ES Francisquito. 
We travelled th hrough the Tejon Pass, and a fine opportunity was thus presented for repeat- 
ing and comparing the observations upon its geology previously made. Granitic and metamor- 
phic rocks were the only formations visible, except a thick accumulation of rudely stratified 
drift or detritus, which rests in the bottom of the valley and is cut by the channel of the creek 
at one side, parallel with the pass, and by side ravines from the high ridges. At the summit, a 
fine view of the bare and arid surface of the Great Basin was obtained. The level surface of a 
dry lake, or extensive pond, was plainly visible, and most persons would have regarded it as a 
sheet of water. The range of mountains bounding this part of the basin on the south, and 
separating it from tpe Pacific slope, were also in full view, and could be traced westward for a 
ia m ine a direction nearly at right angles to the Sierra Nevada, forming a 
i with the southern end of the Sierra at the Cañada de las Uvas. Their 
"m i NEE dos the coil alas the Basin, following the wagon road, 
or trail, and not 1 1 ə ravine which was surveyed a few weeks before. Most of the rocks were hid 
from view by the soil, but those that appeared at the surface were similar to the outcrops in the 
ravine, which, indeed, is but a short distance further south. Encamped at a spring on the hill- 
side among some oak trees. The vegetation is not so dense on this side of the mountains as 
the other. Temperature at 7 P. M., 56°; at 9 P. M., 54°. 
October 11.—' Temperature at daylight 49°. The night was cold. On reaching the lower 
hills, near the margin of the broad slope of the Basin, a succession of outcrops of granitic and 
metamorphie rocks was passed. Portions of the exposures resembled the micaceous granite of 
nn Zen | E en 
