96 
GEOLOGY. 
and several low places, where water had been standing, were covered with a thin coat of fine 
clay, now cracked and curled up. Near one of these low places, we found the remains of an 
Indian hush-house, and the stubble of a barley-field. This barley had been raised at the foot 
of one of the highest sand-drifts. The sand was thus found to rest upon a substratum of clay, 
and beyond the field it was found to have a bluish-gray color, and to he very compact and hard. 
The Indian guide conducted us over this surface of clay to “Pozo hondo,” or Deep Well, a deep 
excavation in the clay made by the Indians to obtain water. It was at the base of a high sand- 
drift, and about twenty-five feet deep, but contained only a little water. It was wide at the 
top, but became smaller towards the bottom, being a funnel-shaped depression. The water was 
obtained by means of steps cut in the sides of the pit, the clay having hardened by drying so as 
to become like stone. This excavation appeared to have been made by the hands of Indians, 
for there were no marks of implements, and the clay that had been removed appeared to have 
been taken out while very moist and plastic. It is probable that it has been gradually formed, 
a little clay being taken out every season, or as often as the water failed or became very low. 
The soil for the whole depth of the well consisted entirely of fine, bluish clay, with a little sand. 
The surface of the ground was nearly level and floor-like, and extended from the base of the 
sand-drifts to the mountain, intersecting the rocky ridges with a sharp and well-defined junc¬ 
tion, like that formed by a sheet of water, or the ice on a frozen lake. The opening to the 
well was shaded by several mezquite trees, as shown in the sketch. 
SAN GORGON0 MOUNTAIN, FROM DEEP WELL. 
The peak of San Grorgono rises in the back ground, the pass being on the right, over the line 
of sand-hills in the foreground. 
We encamped, and before the mules were satisfied with water, it was all exhausted. It oozed 
