250 GEOLOGICAL EEMAEKS. Book II. 
valleys and ravines, without water, where horizontal strata 
of sandstone with superincumbent limestone reappear. 
The Canon Blanco and Canon del Toro are defiles in this 
sandstone which Marcou assigns to the Jura formation. 
Upon a table-shaped mountain of sandstone, near Anton 
Chico, a small place on the Upper Pecos, are again found 
the vegetable remains of the Ocate, with other parts of plants 
appearing like reeds. South of Canon Blanco the country 
again forms an undivided and horizontal plateau, which to 
the west, on the Rio Grande, is bordered by a succession 
of plutonic-metamorphysic, perhaps also volcanic and partly 
sedimentary groups of mountains of steep alpine forms, 
between which defiles descend to the Rio Grande Valley. 
Upon this plateau, at the Ojo de Berendo or Antilope 
Spring, occurs white limestone resting upon sandstone. 
This plateau clearly bears a detached portion of the Jura 
formation of the Llano Estacado. But this formation 
appears in a great measure to have been washed away, and 
the new red sandstone laid bare. The same thing occurs 
near the little Salt Lake, towards which the streams of 
Manzanas, Cuarra, &c, flow from the above-mentioned 
groups of mountains. Over this sandstone the road runs 
through the pass of Cuarra and Avd into the valley of the 
Salado, a salt brook which flows through the new red 
sandstone, and then cuts its way through a ravine of a 
deeper-lying limestone, and through this arrives at the 
valley of the Rio Grande. Our way did not lead us 
through this ravine, but over a steep mountain of lime- 
stone overlying the sandstone, and in this way reached the 
valley of the river above La Joyita. Thus there appear 
here upon the east side of the Rio Grande, in a narrow 
space, three or four different formations which, according 
