DAVIS: THE WASATCH, CANYON, AND HOUSE RANGES. 55 
factors; it may therefore be introduced wherever it is demanded by 
good evidence. Without the aid of modern faulting, compound ero- 
sion cannot account for the forms that certain of the higher Basin 
ranges possess. No combination of deformations and erosions from 
which strong modern faulting is omitted can produce strong ranges in 
close relation to broad intermont basins, such as I have seen in the 
House range of Utah and the Stein mountains of Oregon, to say noth- 
ing of various smaller ranges or of the long Wasatch range on the 
eastern border of the Great basin. 
The attribution of specific dates and values to a compound series of 
Processes, in order more fully to explain the observed details of moun- 
tains structure and form, may be regarded as a refinement of geo- 
logical and physiographical study corresponding to that which is 
made when qualitative work in chemistry is carried forward to the 
Quantitative stage. It is this refinement that in my opinion places 
Gilbert's discussion of the Basin ranges in advance of Spurr’s. 
Frequent mention has been made in the preceding pages of uplifted 
mountain blocks. One member of our party expressed some dissent 
from the view of problem thus implied, and preferred to regard the 
Mountains as relatively quiescent areas, and to regard the intermont 
troughs as depressed “graben.” As far as the locally observed facts 
are concerned, it would be difficult to make absolute choice between 
these two alternative forms of statement and the processes that they 
represent. The only safe statement appears to be that differential 
movement has taken place. Any sort of dislocation that satisfies this 
requirement deserves consideration. The whole region may have been 
uplifted, the mountain blocks more than the trough blocks; the whole 
region may have been depressed, the trough block more than the moun- 
tain blocks; the mountain blocks may have been uplifted while at 
least some of the trough blocks stood still; the trough blocks may 
have been depressed while at least some of the mountain blocks 
Stood still; the mountain blocks may have been uplifted by various 
amounts and the trough blocks depressed by various amounts. 
Until some sufficient means for discriminating among these various 
possibilities are gained, it seems best to maintain an open mind re- 
garding all of them. The meaning of “uplifted block,” as here used, 
is therefore simply that the block is now exposed to deeper erosion 
than it was before the “ uplift ” took place. 
There are certain features of the region described in these pages 
that stand forth in my memory of the excursion as of particular inter- 
est and value. One is the maturely dissected landslide on the western 
