304 



pressions of long linear leaves and endogenous root-like bodies, together 

 with small fucoidal markings. Higher in the bluffs, heavy ledges of buff 

 and reddish sandstone appear, showing a slight inclination down the 

 valley, or southeastward, indicating, in connection with the opposite dip 

 observed at the head of the park, a gentle undulation in the strata, 

 more or less parallel to the metamorphic ridges ten or fifteen miles to 

 the west. 



Looking up the valley from this point, we gain a beautiful view of the 

 Yermejos, showing the peaks to the north of the great truncated py- 

 ramidal cone, framed in between the walls of the gateway. It is with 

 peculiar emotions each re-appearance of their familiar domes is hailed; 

 and so constantl}' have they attended our progress through the parks 

 that it is with equal reluctance we now turn our backs in aclios to these 

 majestic mountains. • Thence the valley continues, closely pressed by 

 the hills, a distance of two or three miles, when they suddenly diminish 

 in altitude, and recede as we approach Cameron's, on the Elizabethtown 

 and Trinidad road, where the stream enters a broad depression occupied 

 by low upland undulations, which are clothed with pine and piiion and 

 extensive grazing-range. This undulating belt probably marks the 

 breaking-down or eastern limits of one of the terrace levels of the Ter- 

 tiary plateau, or a stage in the drainage of the Post-Tertiary basin, whose 

 waters for a time swept the base of this low escarpment. 



Considerable tracts of bottomland, or low, shelving terrace-benches, 

 continue from this point dovvn the valley some nine miles to Mr. Stout's, 

 the border upland gradually increasing in elevation above the deepen- 

 ing bed of the stream, and drawing nearer on approaching the great 

 bend, where they present bold bluffs and escarpments, often made up 

 of immense beds of sandstone. Here the Vermejo nearly doubles upon 

 itself in the distance of about one and a half miles, and in the course of 

 ages it has excavated its channel deep into the Tertiary deposits, which 

 rise in precipitous and frequently vertical walls to the height of sev- 

 eral hundred feet above the shadows that dwell at their base, and which 

 no ray of sunlight penetrates. A practicable bridle-trail traverses the 

 canon, crossing and recrossing the impetuous stream, whose bed is 

 blocked by immense masses of sandstone dislodged from the ledges above, 

 and paved with bowlders, which afford treacherous footing for our ani- 

 mals, winding beneath overhanging ledges, now crossing a thicket-grown 

 miniature intervale, then rising high up on the shoulder of a steep 

 talus of dehris — a bit of journey performed with some degree of misgiv- 

 ing, but remembered with liveliest satisfaction. Below the great bend, 

 a distance of four miles, the stream continues walled in its narrow valley 

 by sandstone escarpments, when it sweeps round a low ledge and opens 

 out below into the gradually-widening level intervale, which extends 

 thence some three miles to the embouchure of the valley into the plains. 



Eounding the high point in the angle south of the valley, the road 

 passes up through shallow depressions, past deep alcoves studded with 

 picturesque castellated rocks and tottering watch-tower pinnacles, out 

 upon the long ijinon covered slope bordering the basin of the Canadian. 



The accompanying profiles are intended to exhibit the general struc- 

 tural features in different parts of the region noticed in the foregoing 

 pages, and the relative position of the various geological elements there 

 met with. 



Fig. 1, plate 48, represents a profile extending easterly from Costilla 

 Pass in the main range, across the narrow belt of overturned Palaeozoic 

 and Mesozoic strata at the base of the mountains, out upon the Tertiary 

 of the Eaton plateau, crossing the head of the Canadian basin, the 



