«^72 REPORT OF NATIONAL MUSEUM, 1893. 



of green is fomid. The quarry has been worked for the last fifteen 

 years only, and is at ])resent the largest producer of onyx in Mexico. 

 Sizes ranging as large as from 2 to 3 feet square can be obtained, which 

 is something extraordinary in Mexican onyx deposits, and the supply 

 in "sighf'seems to be sufficient for several years. The total absence 

 of any color to set off tlie pure white is to be regretted, but as it is, the 

 demand for the stone is sufficient to tax the quarry to its utmost to 

 supi)ly it. 



Directly east from Sopresa, about 4 miles, is found the quarry of La 

 2lesa, lying, as its name indicates, on a level table-topped mountain. 

 The quarry shows quite extensive working, the product being a varie- 

 gated onyx, which, however, lacks the brilliancy shown in the stone of 

 Antigua Salines. It covers an area of nearly 30 acres, being the largest 

 quarry in Mexico. Occasionally quite large pieces are obtained,'but 

 the. average sizes prepared for shipment will not exceed 15 by 10 by 6 

 inches, while pieces as small as 10 by G by 10 inches are also shipped, 

 both to Europe and America. This, however, is the case with all thl 

 quarries, and it is the exception when pieces larger than the first 

 mentioned are exported. 



In addition to the quarries here mentioned there are many others 

 of less importance, either by reason of their small output or from having 

 been worked out. Among these the most interesting, on account of 

 historical associations or past records, are those known as El Mogote, 

 Lajas, Agua Esconda, Desamparo, Mehauntepec, Tepeyac, Tecohico' 

 La Paoma, and La Eeforma. ' 



Baja California.— ThQ last, and perhaps most important of the Amer- 

 ican deposits to be described are also on Mexican territory, but on the 

 peninsula of Lower or Baja California, near the Gulf Coast, and some 

 150 miles south from San Diego. One of these, that at tlie Tule Arroyo, 

 has been already sufficiently described on p. 547. The second deposit, 

 or rather series of deposits, lies in the open desert some 3 to 5 miles to 

 the southwest of the arroyo. The region is one of low rolling hills and 

 flat-topped mesas, with shallow valleys and dry water courses. The 

 prevailing rock, a friable sandstone, with alternating layers of calcare- 

 ous conglomerate and onyx in isolated patches. The surface is every- 

 where covered with irregularly rounded and angular fragments of 

 eruptive rocks from ilie hills in the near vicinity.* Aside from the 

 onyx and the charaeteristic lake bed deposits all traces of spring and 

 lake action have long since disappeared, and (he region is an arid waste 

 with only cacti, "sirios" [Fouquieria splendens) and the agave shaivi in 

 ti\e immediate vicinity, with the mesquite, paolo verdes, stout, low-branch- 

 ing elephant wood {veatchi Cedrocensis) and pole-like fouquieria colum- 

 naris, or giant cactus {cerevs pringlei {!)) like clustered mill logs along 

 the dry water courses or extending for dreary miles along the flat-topped 



*For a detailed account of the geology of the peninsula, see "Geological Sketch 

 of Lower California." by 8. F. Emmons and G. P. Merrill, published in Bulh-tin 

 Ijreotogical Society of America, Ai)ril, 1894. 



