METAMORPHIC ROCKS—GRANITE—WARNERS PASS. 125 
blance to the incrustation on the rocks of the Desert, except in its chemical composition. We 
encamped at the springs, on the same ground where we had camped twice before. The night 
was very cold, and all the ridges were white with snow. 
December 17.—San Felipe to Santa Isabel, 25 miles.—The ridges bordering the San Felipe 
valley are of granitic rocks. Af and about the summit ridge, the highest point on the trail 
between the Pacific and the Colorado Desert, the granite is compact and syenitic, weathering 
into large, rounded, gray blocks, resembling Quincy syenite. Mica is one of the composing 
minerals; this with the hornblende and feldspar -are in small crystals and evenly distributed, 
giving the mass a uniform texture. Oak trees grow luxuriantly on the soil formed by the 
decomposition of this gray granite, while the gneissoidal rocks, a little to the northward, appear 
almost barren, This is the region of trees and vegetation, and to the traveller presents a great 
contrast with the bald rocks and sandy desert between it and the Colorado. 
Before reaching the summit, we left the road and ascended the rocky ridge on the right, 
finding it to consist of gneiss and mica slate, undoubtedly metamorphie rocks. From the top 
of this ridge a long and narrow valley could be seen extending up from the Desert towards 
Agua Caliente, (Warner's.) 
SANTA ISABEL. 
The ground at the summit of the pass was covered with snow about two inches deep, but the 
air was not very cold. We descended the western side of the mountain, and passed the ruins of 
Warner's adobe house, but instead of turning north to our former encampment in the valley, 
turned off to the south on the road to Santa Isabel. This road winds through a narrow and 
well-wooded valley adjoining the southern end of Warner's. The same compact granitic rock 
