254 
GREAT BASIN OVERTHRUSTS 
A. Tectonic, through Folding'. 
1. Simple and direct.King, 1870 
B. Tectonic, through gravity faulting: 
2. Simple and direct.Gilbert, 1874 
V King, 1878 
3. Simple, previously folded.King, 1878 
Russell, 1884 
Diller, 1886 
Le Conte, 1889 
4. Simple, previously folded and planed.Dutton, 1880 
5. Simple, subsequently v^ater sculptured.Davis, 1903 
6. Complex, folded and faulted.Spurr, 1901 
7. Compound, and direct.Lauterback, 1904 
C. Tectonic, through thrust movement: 
8. Simple, probably occasionally.Keyes, 1919 
D. Erosive, through deflation : 
9. Simple, differential wind-scour, mainly independent of 
.Keyes, 1908 
As doubts were beginning to take form, a score or more years 
ago, concerning the validity of the Basin Range hypothesis of 
fault-block mountains, and attention was especially being directed 
to the incongruity and independence of mountain tectonics and 
mountain profiles, it was not expected that the basic significance 
of such gross discrepancies would be so generally missed. Neither 
was the explanation of the origin of Desert Ranges on other than 
tectonic lines entirely appreciated. Later, it was also observed 
that in such connection overthrust activities among these moun¬ 
tains of the Great Basin was a theme of inquiry worthy of the most 
careful consideration and severest test in the field. Little was it 
thought that the quest which has eluded everyone of the host of 
Government workers for fifty years would so suddenly become 
an accomplished fact. 
Gained when he was prosecuting the Fortieth Parallel Survey 
through the states of Utah and Nevada, it was the matured im¬ 
pression of Clarence King that the desert mountain ridges of that 
region were the tops of anticlinal folds which were now largely 
buried in desert waste. Although not strictly literal in a tectonic 
sense, perhaps, the essential quality of the King idea was that the 
Great Basin was a tract of notable crustal compression, and gave 
expression of the typical Appalachian order. This generalization 
was really a chance inference, rather than a carefully wrought out 
concept and it entirely lacked confirmative proofs of quantative 
nature and observational record. 
