28 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
dent faulting of the Wasatch block makes this range a good train- 
ing ground for whoever would go into the desert farther west and 
learn there, one range at a time, what manner of mountains are to. 
be found in the Great basin. l 
THE Canyon RANGE. 
From Nephi to Lemington. We crossed the subdued range west. 
of Nephi by a low notch on the morning of July 15, and descended 
into a broad intermont plain or basin, known as Dog valley, which 
we traversed to the southwest. Here we saw farther westward, but 
not very clearly on account of the increasing dustiness of the air, the 
confluence of the lowering northern end of the Canyon range with the — 
subdued hills that stretch southward from the Tintic range. The 
drainage outlet of Dog valley was by a shallow but rather narrow 
ravine, cut through the rounded hills on the southwest, where the 
uplands were strewn with round-weathered boulders of trachyte. | 
The ravine soon widened and led us southwestward into the eastern 
part of the so-called Sevier canyon in the Canyon range. This is 
hardly a canyon at all, but an open valley, with liberally dissected 
sides, although the rocks exposed in its enclosing ridges seemed to be 
of an enduring nature. ‘They included some gray limestones, appar- 
ently very resistant to arid weathering, abundant red and purplish © 
quartzites, and a very coarse conglomerate with some boulders up to 
five feet in diameter. The strike of all these beds was northeast- 
southwest; their dip was steep southeast or vertical. The openness — 
of the so-called canyon and the abundant dissection of the ridges on — 
its sides suggested that this range, if it ever were a faulted block, must — 
have reached a much more mature stage of post-faulting dissection 
than is the case with the Wasatch. ‘Terraces and silts of Lake 
Bonneville were seen on the sides of the canyon, and extensive deltas _ 
were found at its western end, all now dissected by Sevier river. As 
to the origin of the canyon, there is the manifest possibility that it is 
the work of the Sevier as an antecedent river, whose course was deter- 
mined in the pre-faulting cycle and was persistently held across the — 
uplifted fault block from which the existing range has been carved; | 
but as to the correctness of this easy solution of the problem I shall 
not venture to express an opinion. The topography of the range, as — 
indicated on the Sevier desert map sheet of the U. S. Geological 
Survey, is altogether inaccurate. ‘The contours appear to have been — 
