154 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
are indeed several delicately embossed contouring lines on the spur 
slopes by which the structure of the mass is indicated in the distant 
view; and on climbing the slopes there are abundant small outcrops 
by which the inference from the distant view is confirmed; but as 
a whole the slopes are graded and cloaked with a thin cover of creeping 
waste, so that the observer’s attention is not too soon diverted from 
the study of mountain sculpture by an emphatic exhibition of moun- 
tain structure. 
I first saw the spurs, facets, and ravines of this mountain front from 
the passing excursion train of the International Geological Congress in 
1891; but they were then only regarded as “peculiar.” They were seen 
a second time on returning from a Colorado canyon excursion in 1900, 
and on that occasion, although they were then again observed only from 
passing trains northward on one road in the morning, and southward on 
another in the afternoon, the possibility and necessity of explaining 
them as a result of erosion on a faulted block was recognized. During 
the summer of 1902 my party made a special visit to these significant 
spurs, walked along their base for a short distance, ascended the slope of 
one of the facets, and came down again by the ravine alongside of it. 
There seemed to be no escape from the conclusion that extensive and 
recent faulting of the mountain block is here indicated, not only by the 
complete absence of the mountain rocks west of the almost rectilinear 
base line, as already set forth, but also by the detail of form on the 
mountain face, and particularly by the well-defined facets in which the 
spurs terminate. 
The late afternoon view of the Wahsatch range from the shore of Utah 
lake brings the mountain forms clearly forth. The eye, after wandering 
along other less intelligible parts of the range, turns repeatedly to the 
block north of Spanish fork canyon with enjoyment of the fuller mean- 
ing found there. Elsewhere one’s curiosity is excited ; there it is satis- 
fied. After the sharply defined terminal facets of the mountain spurs 
are found to be systematic elements of form in the Spanish Wahsatch, 
they may be recognized in many other parts of the range, but nowhere, 
so far as I have seen, with the model-like distinctness of development 
that is exhibited in the example just described. 
When the Wahsatch near Provo is seen from a point not too near its 
base, several spur-facets may be distinguished between the canyons and 
ravines by which the mountain front is scored; but the edges of the 
facets are dull, like the edges of a crystal of apatite. In the Spanish 
block, the sharp-edged facets tempt one to sketch in outline: in the 
