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Show 108 i. n. Phosphoric acid 29.57 32.86 Alumina 29.17 40.19 Water , 18.85 19.34 Oxide of copper 4.04 5.27 Protoxide of iron ; 4.35 2.21 Lime 1.61 Silicic acid 12.57 Protoxide of manganese 0.36 100.16 100.23 Large excavations in the turquoise- bearing bill of Los Cerillos tend to testify that this gem was eagerly sought after years ago. The Spaniards, on enteriug Mexico, found ornamental jewelry made fro'tn this g « m in many Indian towns, (" or a long time, however, it was a mystery to them in which locality this gem, called by the Mexicans, to this day, " chalchihuitl," was found ; said locality is the Cerillos. As an instance of the spread of this gem by the Indians, it may be mentioned that Mr. Lock-wood, of this survey, found a small, perforated, polished plate of it amid broken pottery, on a peak, 11,000 feet in height, of the Sierra Blanca, in Arizona. From Los Cerillos we proceeded toward the neighboring Placer Mountains, encountering in the numerous caiions seams of coal, corresponding, in chemical composition, to anthracite; to this attention is called in vol. Ill of the Survey Reports. Farther np along the base of the Placer Mountains, carboniferous limestone is met. with skirting the foot of the masses of Azoic rocks which compose the Placer Mouutains. . The Zandia Mountains bordering these in the southwest represent quite analogous features. With regard to mines it may be stated that, while the former contain important gold- mines, the latter have good copper- ore. Between the Placer Mountains and Santa Fc" we cross several valleys of erosion, iu . which the Triassic beds with their characteristic fossil- wood are well exposed. At Santa F6, however, near the base of the mountains, is again found the Carboniferous limestone. With regard to the Rio Grande Valley, may be mentioned the existence of Tertiary fresh- water deposits near Algodones; also, numerous exposures of brown coal, especially farther south. There is one 3 feet thick near Dona Ana and Mesilla, another at Robledo, near La Joya, north of Fort Craig, and one at San Felipe. Other coal- beds exist in the range Madalena, in Tijeras Cafion, five miles east of Algodones, west of Las Lunas, in the valley of the Rio Puerco, four miles above Anton Chico, and in the valley of the Rabbit- ear Creek. A fact of some interest is, that almost all the tributaries of the Rio Grande carry turbid waters, which become exceedingly muddy after rains. The quantity of material transported by this stream down to the gulf is immense. Chama, Jemez, and Puerco rivers deserve special mention. Thus are agencies here energetically at work to destroy the older formations and build up new ones at the bottom of the Gulf of Mexico. THE MOUNTAINS BETWEEN SANTA FE AND LAS VEGAS. That portion of the Rocky Mountain range which separates the cities of Santa Fe and Las Vegas extends but little farther south, and terminates near the valley of the Gali8teo. Once more this mighty range rises to gigantic proportions before dying out in the plain. Unlike other portions of this range, and unlike most other mountain systems in New Mexico, this mighty elevation between Santa Fe" and Las Vegas is free from more recent eruptive rocks; basalt, trachyte, and rhyolite being absent. Nevertheless, these mountains were not in a state of repose iu older epochs, as shown by the upheaved sedimentary ridges along the western and southern base, and the red granite thrown up during the Carboniferous epoch. Taking a bird's- eye view of this region, we see the old Azoic rocks occupying the larger part of this area. Of sedimentary rocks, none more recent than the Carboniferous are visible, and these are principally in the valleys of the streams; but, proceeding into lower regions toward the base of the mountains, we come gradually to the Triassic and Cretaceous ( probably, also, Jurassic) strata. The whole mountain mass between Santa Fe" and Las Vegas is divided into two branches, or arms, by the Pecos River, the western forming the Santa Fe" range, the eastern the Gallinas Mouutainsf the Gallinas Creek here takiug its rise. Both these branches form a Heries of steep ridges, elougated spurs, rocky slopes, aud deeply excavated valleys. The most prominent peak of the westeru range is Baldy Peak, with an . average elevation of 12,400 feet above sea- level, whose summit is often covered with snow in midsummer. A great number of streams take their rise in these mouutains, the Santa Clara, ( or Rio de Canada,) Pojoaque, Tesuque, aud Santa F< 5 Creek flowing to the west and southwest, the Pecos and its tributaries, Macho, Vaca, and Tecolote toward the south, and the Gallinas toward the east, at least until it leaves the foot- hills of the mountains. The mountains are partially well- timbered, partially covered with 1 alien timber, and partially barren. |