DAVIS: MOUNTAIN RANGES OF THE GREAT BASIN. 139 
346) ; further east the maps of the 40th Parallel survey indicate Meso- 
zoic strata. West of the mountain base, no rocks are seen in place ; 
the gravel beaches and deltas of Lake Bonneville descend to the alluvial 
plain that slopes under the shallow waters of Utah lake. 
About twelve miles southeast of Provo, the Spanish Wahsatch, lying 
next north of Spanish fork canyon, is even more emphatic in its testi- 
mony for block faulting. A view along its base is given in Plate LB: 
Its rock layers are nearly horizontal or dip gently eastward. Some sig- 
nificant details of its form will be considered later. 
The Wahsatch near and northwest of Ogden presents several signifi- 
cant features, even when seen only from a railroad train. Its base line is 
here of moderate curvature, and manifestly traverses various structures, 
as indicated both by form and by color. The mountain front rises 
abruptly and continuously from the base line, except for brief inter- 
ruptions in narrow-mouthed canyons. 
Figure 4. 
Rough cross-section of the Provo Wahsatch, looking north. 
The features of this range and of several others further west, as seen 
from the passing train, were so accordant with the features more deliber- 
ately observed near Provo that the burden of proof seems to me to rest 
with those who regard the ranges as other than carved fault blocks; but 
while observations from a train may have a high value to the observer, 
I am well aware that they will not be regarded as convincing by others, 
especially not by those whose habitual work in paleeontology, petrography, 
or minute stratigraphy has given them no acquaintance with the value 
of large elements of form in physiographic problems, even though these 
elements be only hastily observed from a car window. 
During a stage ride northward from Winnemucca, Nev., into southern 
Oregon, I passed the Santa Rosa and Pine Forest ranges, both of which 
exhibited very clearly the gently curving base line, regardless of rock 
structure, and the bold mountain front, continuous except for sharp-cut 
canyons, that are essentially characteristic of carved-block mountains. 
