DESCRIPTION OF THE COUNTRY. 53 
character of the country, the specimens collected, the reports of early Spanish explorers, and 
from Mexican traditions, it seems probable that large amounts of treasure exist at Gran Quivira, 
among the San Francisco mountains, in the Aztec range, and upon Williams' river. "The 
salineras or salt-pits upon the plains between Rio Pecos and the Del Norte will become another 
important source of mineral wealth to the settlers of New Mexico. 
Leaving the coal-bearing strata that crop out upon the eastern slope of the Zandia range, 
we find the centre of the line of dislocation of the Rocky mountains, where exist the rich 
auriferous veins already referred to, composed of serpentine and granitic rocks, affording a good 
building material. We then enter the valley of the Rio Grande where the granite is covered 
by drift and alluvium. From the Del Norte to the volcanic peak of San Mateo there exist 
white, friable sandstones of the trias or jurassic formation. Some portions of the cliffs which 
bound the edges of the mesas have considerable hardness, and, by quarrying, a good material 
for embankments, bridges, and other constructions, could be obtained in the vicinity of the 
route. As we approach San Mateo, streams of disintegrating lava are frequently found in the 
valleys. ‘‘ Near the culminating point of the Sierra Madre the trias is replaced by the car- 
boniferous limestone; then for a distance of twelve miles the rocks are eruptive granite, 
gneiss, and mica schist. Beyond, on the western declivity of the Sierra, comes the carbonifer- 
ous again, the beds of the trias, and finally the white and yellow sandstones of the jurassic, 
with streams of volcanic lava in the valleys. Inscription Rock, and the whole mesa that 
extends nearly to Zuiii, are formed of the jurassic rocks." The vertical faces of these cliffs are 
covered with ancient Indian or early Spanish inscriptions. From the dates of the latter, it 
appears that more than two centuries have elapsed since they were executed, and the crumbling 
of the rock from atmospheric influences has not caused them to be effaced. This fact affords a 
proof of the value of the jurassic sandstones for a building material. They may be easily cut 
into blocks of the required dimensions, and in this climate, where the exfoliation by frosts is 
exceedingly slight, it would prove a durable material for railroad constructions. In many locali- 
ties upon the line, we have, as before stated, rocks of the primitive or metamorphic formations ; 
but so much of the route is bordered by sandstones that the above record of their durability 
becomes highly important with regard to their fitness for railway purposes. 
The triassic rocks extend from Zuñi to the volcanic peaks near the head-waters of Rio Verde ; 
containing sandstone and red clay, with dolomite and gypsum. Thence across the Aztec range 
to White Cliff creek, the sedimentary and granitic rocks have in many places been covered by 
lava and basalt; but among the former, we find ‘‘ magnesian limestone, the sandstone of the 
coal measures, and the carboniferous limestone." In the vicinity of Partridge creek, there are 
indications of coal. This region is believed to be rich in precious metals; but, being traversed 
by us in mid-winter, when a thin sheet of snow covered a great portion of the surface, our 
examinations with regard to this subject were imperfect. 
Williams’ river cuts through low mountain chains of eruptive or metamorphic rocks, in which 
Mr. Marcou found *' several veins of argentiferous lead.” The region more directly west, from 
White Cliff creek to the Mojave villages, is mostly covered with diluvial drift, forming a smooth 
surface, and plains of gentle inclination. Granitic rocks are exposed upon the mountain ranges 
that lie upon the north. West of the Colorado, the Paiute mountains are crossed, where sienitic 
granite is found alternating with sandstones and limestones. The little cafion on the Mojave 
river will probably afford good quarries of stone. 
* In the Cajon Pass," were discovered ‘‘sienite, trap, and serpentine, exactly similar to 
those found between Rough and Ready, Grass Valley, and Nevada City, and which contain the 
veins of auriferous quartz.” As specimens were obtained at Los Angeles ‘very rich in gold, 
coming from the Cajon Pass, it is more than probable that this point will one day be one of the 
richest places in California.” 
‘t In an economical point of view," continues Mr. Marcou, ‘the eruptive rocks, which torm 
almost the whole country between Cactus Pass and the Cajon Pass, will furnish excellent mate- 
