PERMO-CARBONIFEROUS OF NORTHERN NEW MEXICO 5 
famous canon known as El Cobre, so named because of the indica- 
tions (indications only) of copper long known there. From thence 
the expedition followed the valley of the Puerco to the embouchure 
of its chief tributary, the Poleo (Arroya de Agua). Later a brief 
trip was made to the valley of the Gallina, and as far west as the 
Wasatch deposits in Sandoval County. 
From Espanola to Abiquiu the road follows the sandy valley of 
the Chama, bordered by Tertiary deposits, coarse white sandstones, 
often eroded into typical badland forms, and leading up to lava- 
capped table-lands. Three or four miles west of Abiquiu the 
Tertiary sandstones lie immediately upon heavy beds of red clays 
and red sandstones of Triassic age. In the immediate stream bed 
Fic. 2.—Map of region about Abiquiu showing location of El Cobre Cajion 
of the Cobre creek we observed conglomerates twenty or more 
feet in thickness, composed of quartzite bowlders reaching six or 
eight inches in diameter, and almost devoid of binding matrix. 
Farther northwest and toward the entrance into the Cobre basin 
there are fifty or more feet of red and variegated clays, which in turn 
are underlain by from fifty to seventy-five feet of more massive 
sandstones, with a more or less persistent conglomerate pebbly 
layer beneath them, yielding phytosaur remains. It is through 
these sandstones that the outlet of the basin occurs in a narrow but 
not deep gorge. 
E] Cobre Cafion or basin is formed by the erosion of an unsym- 
metrical dome-shaped anticline more or less faulted on the north- 
eastern and southeastern sides, the brim formed everywhere by the 
massive sandstones of basal Upper Triassic age, the strata sloping 
