MINDELEFF | NATURAL FEATURES OF THE CANYON 87 
The dimensions have already been given. The pinnacle is perfectly 
plumb. 
The rock of which the canyon walls are formed is a massive sand- 
stone in which the lines of bedding are almost completely obliterated. 
It is rather soft in texture, and has been carved by atmospheric erosion 
into grotesque and sometimes beautiful forms. In places great blocks 
have fallen off, leaving smooth vertical surfaces, extending sometimes 
from the top nearly to the stream bed, 400 feet or more in height and 
as much in breadth. In the lower parts of the canyons the walls, some- 
times of the character described, sometimes with the surfaces and angles 
smoothed by the flying sand, are generally vertical and often overhang, 
descending sheer to the canyon bottom without talus or intervening 
slopes of débris. The talus, where there is any, is slight and consists 
of massive sandstone of the same character as the walls, but much 
rounded by atmospheric erosion. The enlarged map (plate XLII) 
shows something of this character. 
Near its mouth the whole bottom of the canyon consists of an even 
stretch of white sand extending from cliff to cliff. <A little higher up 
there are small areas of alluvium, or bottom land, in recesses and coves 
in the walls and generally only a foot or two above the stream bed. 
Still higher up these areas become more abundant and of greater extent, 
forming regular benches or terraces, generally well raised above the 
stream bed. At the Casa Blanca ruin, 7 miles up the canyon, the bench 
is 8 or 10 feet above the stream. Hach little branch canyon and deep 
cove in the cliffs is fronted by a more or less extended area of this 
cultivable bottom land. Ten miles up the talus has become a promi- 
nent feature. It consists of broken rock, sand, and soil, generally over- 
lying a slope of massive sandstone, such as has been described, and 
which occasionally crops out on the surface. With the development of 
the talus the area of bottom land dwindles, and the former encroaches 
more and more until a little above the junction of Monument canyon 
the bottom land is limited to narrow strips and small patches here and 
there. 
These bottom lands are the cultivable areas of the canyon bottom, 
and their occurrence and distribution bave dictated the location of the 
villages now in ruins. They are also the sites of all the Navaho settle- 
ments in the canyon. The Navaho hogans are generally placed directly 
on the bottoms; the ruins aré always so located as to overlook them, 
Only a very small proportion of the available land is utilized by the 
Navaho, and not all of it was used by the old village builders. The 
Navaho sites, as a whole, are far superior to the village sites. 
The horticultural conditions here, while essentially the same as those 
of the whole pueblo region, present some peculiar features. Except 
for a few modern examples there are no traces of irrigating works, and 
the Navaho work can not be regarded as a success. The village build- 
ers probably did not require irrigation for the successful cultivation of 
their crops, and under the ordinary Indian methods of planting and 
cultivation a failure to harvest a good crop was probably rare. After 
