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Show 202 The Las Vegas range was examined in the southern portions only. In crossing the range, en route from Santa F l to Las Vegas, the valleys of the Rio Pecos, Rio La Cuera, and Rio Vaca were crossed. Each of these rivers affords a fine section of bluish limestone, containing many crinoids and brachiopods, similar to the rock at Santa Fe\ I think the limestone forming the southern part of the Las Vegas range is identical in age with that of Santa Fe\ The central and northern portions of the Las Vegas range contain archsean rocks, but as Dr. Oscar Loew has described this region in the annual report for 1875, reference may be made to this report for a detailed account of the geology of the range. This chapter on the mountain- ranges may be concluded by a few general remarks on the individual ranges. The only ranges containing ore- deposits of any importance are the Taos and Cimarron ranges. In the Cimarron range both placer and vein mining are carried on, but in the Taos range there is vein- mining only. The predominating rocks entering into the composition of the various ranges may be stated as follows: Tne Spanish Peaks are trachyte; the Culebra range is granite; the Cimarron range is granite and granulite; the Taos range is granite and syenite; the Mora range is sandstone; the Santa Fe" rauge is granite; the Las Vegas range is granite and limestone. The Culebra range contains the highest peaks; Culebra Peak, the culminating point, being 14,040 feet above the sea- leveL Cimarron range is the longest of all the ranges, being 50 miles long. Respectfully submitted. A. R. CONK LING. Lieut. GEO. M. WHEELER, Corps of Engineers, in charge. APPENDIX H 5. REPORT UPON THE OPERATIONS OF A SPECIAL NATURAL- HISTORY PARTY AND MAIN FIELD- PARTY NO. 1, CALIFORNIA SECTION, FIELD- SEASON OF 1875, BEING THE RESULTS OF OBSERVATIONS UPON THE ECONOMIC BOTANY AND AGRICULTURE OF PORTIONS OF SOUTHERN CALIFORNIA, BY DR. J. T. ROTHROCK, ACTING ASSISTANT SURGEON, UNITED STATES ARMY. UNITED STATES ENGINEER OFFICE, GEOGRAPHICAL SURVEY WEST OF THE 100TH MERIDIAN, Washington, D. C, January 19,1876. SIR : In compliance with your instructions of January 12,1876,1 have the honor to submit the following report of my observations in connection with the operations of the special natural history party and main field party No. 1, of the California section, field season of 1875. The work of the season may fairly be considered as commencing at the island of Santa Cruz? off Santa Barbara coast. This island, lying south of Santa Barbara and probably distant from it about 30 miles, is nearly 17 miles long, and at its widest portion about 6 miles across. It is much narrowed near its middle by bays making in from the northern and southern coasts, and from one point to the other a wagon- road or trail exists. The island is almost wholly given up to sheep- raising. It is estimated that in the spring of 1875 there were not less than 60,000 herds of them on the island. In June 15,000 were killed for the hade and tallow alone; the offal being carted down to the shore and cast into the water, attracting immense numbers of fish to the spot. The island is rugged in the extreme; one point is said to attain to a height of 2,500 feet above sea- level. It is from one end to the other little else than a succession ot rocky hills with intervening gulches rather than valleys. In a few places agriculture to a limited extent is carried on; only enough is raised to meet the needs of the population, if indeed it does this. Here and there a level surface intervenes between the base of the hills and the ocean. What its capacity for agricultural purposes may be I am not able to say, as there is not enough water for irrigation, and as, in my opinion, the mists from the ocean would be altogether too precarious to depend upon. I am. however, bound to state that in one or two places pepper- trees had been planted ana were growing vigorously without care, and that some little grain is cultivated near Prisoner's Harbor. It appears that at the time Cabrillo made his voyage along this coast, ( 1542,) these islands were timbered clear to the water's edge, and we now have abundant signs of forests that have disappeared at the sea- level, where their stumps and roots still remain in situ. At present the indigenous forest- growth is limited to the highest summits of the island. A dense under- growth does in many places descend lower, but it never obtains to the dignity of a forest. It is simply a thicket. Among this, however, is |