TRAP DYKE AND SAND STONE FORMATIONS, between Camps 21 and 22 Sept. 12th

PS Duvals Steam with Press Philad

Cañon.) This cañon, which is about a quarter of a mile in length, is, on account of its high enclosing walls, and the well-defined character of their stratification, beautiful. The walls, which are nearly vertical, are probably from three to four hundred feet high. The formation is a red friable sandstone; the stratification, which discloses a dip of about ten degrees towards the east, as also the line of cleavage, being very distinctly marked. The width of the cañon is about one hundred feet, a small stream finding its way through its bottom. This cañon differs from that of Chelly, in the face of its walls not being so smooth; in not presenting as large unstratified masses; and having a talus of debris at the foot of the walls.

This cañon passed through, the route turned almost due south; following, for the remaining portion of the day, a succession of wide, shallow, fertile valleys, which are generally bordered on their eastern side by escarpment walls of a white and red sandstone formation.

Just after we debouched from the Cañoncito Bonito, a most singular prospect of detached turret-like rocks appeared skirting the valley just referred to on its eastern side. And down the valley, in a more southerly direction, a trap dyke of a striking character presented itself, a short distance to our front. For a sketch of this view, see Plate 57. This dyke, on examination, I found to present a most interesting exhibition of igneous action. and vertical protrusion. Its height above the plain is some three or four hundred feet; its breadth, one hundred and fifty; and its length, about two hundred yards. Its strike is nearly due east. Here can be seen, in the same formation, rocks that have been once perfectly fused, and then cooled under pressure, the effect being to make them more dense; rocks that have been fused, and then cooled under the pressure only of the atmosphere, the effect being to make them scoriaceous; and rocks that look as if they had not been fused, but merely baked. I noticed also here, in a sort of cave, a large mass of the same kind of black, agglutinated, pitchy substance I have already described as having been seen, August 24, in the rocks of the Cañon de la Copa. It was here, as there, intermingled with bits of straw, &c. These are the only trap rocks we have seen near our route since we left our eighteenth camp.

About nine miles from our last camp, on the route, is Siene

guilla de Maria, where we found some very cold water, and grass of an excellent quality. The supply of water here is probably perennial. Three miles further, some very singular whitish abutment rocks, probably of sandstone, are to be seen on the left, jutting out from among rocks of a sandstone character and red color. The difference in the complexion and shape of the former of these rocks indicates a superior hardness, in the formation of which there are prominences. Four miles further, just to the right of the road, appears a beautiful exhibition of horizontal stratification, terminating in one of a bent, semicircular character-the strata (red sandstone) in the last case being concentric, like the coatings of an onion, and disclosing themselves both by a side and end view. Eighteen miles from our last camp, we crossed a rough, bad place, where some little labor would be required to make it practicable for wagons. Two miles further, immediately on the left of the road, are two enormous hemispherical masses of solid sandstone rock; the radius of one of them being about one hundred feet.

After a march of 23.02 miles reaching a babbling streamlet of excellent water, which heads in a spring not far distant, and the vicinity affording fine pasturage and plenty of fuel, we encamped.

The soil to-day along the route has been of an argillaceous character, and looks as if it might produce well. As usual, pine and cedar, of rather a scrub growth, have constituted the timber. A deer was killed by a soldier this morning, after running the gauntlet of numerous shots from the command-myself, among the number, throwing away a pistol shot. This is the first deer which has been killed by any of the party. The scarcity of this kind of game may therefore readily be inferred. Indeed, a more wretched country for game of every kind I have never seen than that we have been traversing since we left Santa Fé. A rattlesnake was also killed to-day, and a wildcat is reported to have been seen. I noticed to-day, for the first time on the march, a flock of blackbirds. I have also seen, along the route, a species of swallow different from anything of the kind I have ever before met with. It is peculiar in being, a large portion of it, both on its back and its belly, white. It probably is a bank swallow.

It is reported that there is a wagon route from Cañoncito Bonito to the Pueblo of Jémez; but as I have no certain knowledge