EROSIONAL ORIGIN OF THE GREAT BASIN RANGES 
CHARLES R. KEYES 
It is not at all probable that the origin of the mountain ranges 
of the Great Basin of western America can find adequate and satis- 
factory explanation by a single simple hypothesis. Nor can it be 
advantageously postulated that the genesis of the mountains is the 
same in the various parts of that vaster desert region of which the 
Great Basin is only a minor portion. In general all recent observa- 
tions go to show that these mountains as they exist today must be 
regarded as the outcome of the action of several sorts of geologic 
forces, operating sometimes severally and sometimes in conjunction, 
at diverse times and with different degrees of intensity. 
The relative ascendency of the several geologic processes in shaping 
the larger relief features of the desert region has remained until recently 
an indeterminate quantity. It is this aspect of the subject that has 
been all but entirely overlooked. This neglect has led to very diver- 
gent opinions, as is shown by a full dozen of distinct hypotheses ad- 
vanced to explain the origin of the Basin ranges. 
In the consideration of the origin of the American desert moun- 
tains, it is usually assumed that they are strictly structural features. 
‘That they may have been fashioned, partly at least, by other means 
is a Suggestion which is only beginning to attract the attention which 
it merits. Present indications are that erosion—eolian erosion—must 
be reckoned with as one of the potent factors in desert sculpturing. 
Many descriptions of the Great Basin ranges have been published. 
Notwithstanding this fact there has not yet appeared, as Davis’ 
well says, ‘“‘any detailed statement of the theory by which they are 
explained; the essential consequences of the theory have not been 
explicitly formulated; the criteria by which a fault-block mountain . 
may be recognized in early or later stages of dissection have not been 
defined.” 
t Bull. Mus. Comp. Zool., XLII, p. 112, 1903. 
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