HUECO MOUNTAINS.—LOS CORNUDOS. 
13 
large masses of dark-grey sandstone -thrown up in the utmost disorder and confusion, having 
numerous holes and caverns which have often served the Apaches as hiding-places.” 1 
It is not impossible that these dark-grey blocks, although resembling sandstone, were the 
compact and fine-grained granite just described, or possibly Carboniferous limestone. Mr. 
Byrne afterwards states that the natural wells of the Cornudos were, as at the Hueco tanks, 
reservoirs in the rOck, which was similarly piled up in confusion and disorder. He also states 
that these rocks are of a kind of granite or gneiss. Mr. Bartlett, the former boundary commis¬ 
sioner, who examined the Hueco mountains carefully, found them to be composed chiefly of 
granite. He says : “The formation here is granite in place, rising from 100 to 150 feet above 
the surrounding plain, and covered with large boulders piled up in every imaginable form. In 
many places, the rock projects or overhangs; and in others, frightful chasms, as though rent 
asunder by some violent concussion, appear.” 2 At other places he found the deep, circular 
holes in the rock, made by Indians in pounding their corn; and these were in granite, and from 
twelve to fifteen inches deep. Such holes as these are exceedingly common in California, and 
are always in the most compact granite, as, undoubtedly, any granular rock like sandstone 
would be constantly abraded and fill the meal with grit. The descriptions which Mr. Bartlett 
gives of the overhanging rocks with their broad, flat surfaces, upon which many inscriptions have 
been made, indicate the presence of stratified rocks, although it is not at all iinprobable that such 
surfaces are presented by the masses of granite. When travelling through the Hueco Pass, 
however, Mr. Bartlett mentions the occurrence of grey limestone, which rose up on each side of 
the way like walls. At the same time, the great mountain could be seen half a mile beyond, 
with perpendicular sides of granite. 
From these facts, and other evidences, I conclude that the Hueco mountains are principally 
granitic and metamorphic, and that stratified rocks occur on the flanks of the range; whether 
these are the Carboniferous strata, or not, it is of course impossible to decide without specimens 
and fossils. 3 
The peculiar broken character of this granite, the masses being of great size, and lying piled 
together in confusion, has resulted from the gradual breaking up of the mass in situ, and not 
from the action of floods, by which the blocks have been transported like boulders to their pres¬ 
ent positions. It is probable that the whole mountain is traversed by fissures in several direc¬ 
tions, so that the whole rock is, in a manner, cut up into blocks, which become loosened and 
detached by weathering, and roll down its sides, accumulating in rude piles around the base of 
the cliffs. 
Los Cornudos .—According to Mr. Byrne, this mountain is about five hundred feet high, and 
consists of huge masses of rock, scattered about in the utmost disorder and confusion. It was 
also his opinion, as has already been stated, that they were composed of a kind of granite or 
gneiss. I find the following observations on this rocky elevation in the narrative of Mr. 
Bartlett: “This wonderful mountain, of which it is impossible to convey any adequate idea 
by description, is a pile of red granite boulders of gigantic size, thrown up abruptly into the 
plain. The boulders are mostly of an oblong shape, with their largest diameter vertical; they 
are rounded, and often highly polished.” 4 It is evident that, in respect to the broken, loose 
character of the rock, it much resembles that of the Hueco mountains at the wells, and, like 
it, appears to be a quantity of boulders piled together. This, as I have shown, arises from the 
decomposition of the rock, and its gradual breaking up along lines of fissure or of cleavage. 
Mr. Bartlett’s description will apply very truthfully to an erupted rock somewhat basaltiform; 
and I am inclined so to regard it. Moreover, I find in the collection one specimen from this 
locality—Ho. 73 of the catalogue and description. The label states that it was taken from the 
1 Report on the Route from Fort Smith to Santa Fd, p. 199. 3 J. R. Bartlett, Personal Narrative, i, p. 170. 
3 Lieutenant Bryan states that the rocks on each side of a part of this pass are in regular layers, and consist of limestone 
and granite. [Reconnaissances in New Mexico and Texas, p. 23.] 
4 J. R. Bartlett, Personal Narrative, i, p. 129. 
