458 J, W. Powell—G@eological Structure of the country 
the conglomerate, but now carried away by erosion. Underly- 
ing this cap are variegated sandstones and marls. The whole 
group is probably of lower Triassic age. The silicified woods 
so abundant here are called by the Indians who inhabit the 
country, Shin-ar-ump; or, The arrows of Shin-at-av. (Shi- 
nauay is the Hercules of their mythology.) To the cliffs they 
give the name Shin-ar-ump Mu-Kwan-i-Kunt, and we have 
adopted as the English name, Shin-ar-ump (or Arrow) cliffs. 
Still passing to the north a few miles, we reach the foot of a 
second line of cliffs, composed of red sandstone, and beds 0 
lighter color, which are stained red on the surface. To this 
line the Indians have given the name Un-Kar Mu-Kwan-1- 
Kunt; we have adopted the translation, Vermilion Chiffs. This 
assing on to later formed beds, until he meets with a line 
a point many miles east of the Colorado River,—a distance of 
nearly 200 miles; the Vermilion Cliffs have been traced some 
what farther, as have the Gray Cliffs. The Pink Cliffs are 
