sandy bed it is often possible to obtain a limited supply of water.
This is well known to the Navaho, and 90 per cent of the houses of this
region are located within reach of the wash, whence the supply of water
which the Navaho deems essential is procured.

On the western slope of the mountains and in the canyons and cliffs of
the high table-lands which form the western part of the reservation,
the water supply, while still scanty, is abundant as compared with
the eastern part. In the mountains themselves there are numerous small
streams, some of which carry water nearly all the year; while here and
there throughout the region are many diminutive springs almost or quite
permanent in character. Most of the little streams rise near the crest
of the mountains and, flowing westward, are collected in a deep canyon
cut in the western slope, whence the water is discharged into Chinlee
valley, and traversing its length in the so-called Rio de Chelly,
finally reaches San Juan river. But while these little streams are
fairly permanent up in the mountains, their combined flow is seldom
sufficient, except in times of flood, to reach the mouth of Canyon
Chelly and Chinlee valley. However, here, as in the Chaco, there is an
underflow, which the Indians know how to utilize and from which they
can always obtain a sufficient supply of potable water.

The whole Navaho country lies within what the geologists term the
Plateau region, and its topography is dictated by the peculiar
characteristics of that area. The soft sandstone measures, which are its
most pronounced feature, appear to lie perfectly horizontal, but in fact
the strata have a slight, although persistent dip. From this peculiarity
it comes about that each stratum extends for miles with an unbroken
sameness which is extremely monotonous to the traveler; but finally its
dip carries it under the next succeeding stratum, whose edge appears