514 ALLEN DAVID HOLE 
Deep Creek, the valley of the San Miguel is a canyon with pre- 
cipitous walls 1,000 feet high. Beyond the mouth of Deep Creek 
the canyon gradually increases in depth until, at Sawpit, at the 
northwest corner of the quadrangle, the stream is 1,700 feet below 
the level of the edge of the plateau in which it has cut its channel. 
Drift in the valley of the San Miguel.—Drift in the form of valley 
train is found up to too feet above the stream at various points as 
at Newmire and Sawpit, and beyond the boundaries of the quad- 
rangle; but the lowest point reached by the ice in the more recent 
stage of glaciation is near the mouth of Deep Creek. At this point 
the north wall of the valley is precipitous, its south wall worn and 
weathered until, although still steep, it has become a long, retreating 
slope instead of a precipice. On the north side of the river here and 
for about one and one-fourth miles to the eastward, no glacial 
débris is discernible such as could be classed as morainal. The 
bare cliff faces afford no place for its lodgment; and even if once 
left on the more level area beside the stream, it has been either 
washed away or covered by irregular heaps of talus which have 
fallen since the ice withdrew. 
On the south side, however, the longer, less steep canyon wall 
has allowed the glacial débris to remain in sufficient quantity to 
mark the approximate position of the edge of the ice at the time of 
its farthest advance. The débris consists of bowlders in variety, 
some with characteristic glacial striae, exposed at various points 
along the boundary as mapped and to the east of this line. In sharp 
contrast, the slope to the west of the boundary is covered by black 
soil, usually with few rock fragments, or, where they exist, consisting 
almost entirely of fragments of bed rock. 
Between Bilk Creek and Lake Fork the south wall of the canyon 
becomes somewhat steeper; in the upper 200 or 300 feet, however, 
the slope affords lodgment for drift, forming a well-marked narrow 
shelf for a distance of more than a fourth of a mile. The top of 
the mesa to the south is entirely covered with drift to a depth 
which at its maximum may reach 200 or 300 feet. On the north 
side of the canyon, the wall is still precipitous, with no possibility 
for the lodgment of drift; but at a point opposite the railroad 
bridge over the San Miguel River, drift appears on the edge of the 
