boutwell] ORE DEPOSITS OF BINGHAM, UTAH. Ill 
flowed and submerged an ancient topography. Nothing bearing upon 
the source. of this rock has been found since the work of Mr. Emmons 
in connection with the early survey of this region, when he determined 
that— 
the Traverse Mountains, which form a partial connection between the Wasatch 
Range and the Oquirrh Mountains, * * * seem to he composed mainly of 
trachyte, the flows of which extend * * * along the foothills of the Oquirrhs 
so far as the mouth of Bingham Canyon. « 
The date of the porphyry intrusions is not definitely fixed, although 
it was probably earlier than the date of the extrusion of the volcanic 
flows, and abundant underground evidence proves that it was earlier 
bhan the late faulting on northeast-southwest fissures, earlier than the 
period of mineralization on those fissures, and probably earlier than 
jhe Assuring which preceded this period of mineralization. 
Correlated studies, which the writer is now undertaking in another 
leld, will, it is believed, throw much light upon the geological history 
)f the igneous rocks of Bingham. So far as known, these extrusives 
lave never been found to carry mineral values. An interesting eco- 
lomic problem associated with this andesitic flow involves the east- 
vard extension of ore bodies. For if the pre volcanic land forms sim- 
dated present forms, and the andesitic breccia simply blankets an 
earlier surface, then there is no structural reason why the ore bodies 
n Carboniferous sediments may not be followed eastward under the 
olcanic flow. On the other hand, if this volcanic mass broke up at 
>r in proximity to the present surface contact, then it is probable 
hat this contact descends in depth approximately vertically and 
runcates the ore bodies. 
Structure of the range. — The general structure of the Oquirrh 
tange, so far as it has been studied, is characterized by broad exten- 
ive folds and complex fracturing and faulting on a small scale. It 
s not improbable, however, that further field work, which shall 
xtend our knowledge beyond the limited areas that have thus far 
»een studied in detail, will reveal extensive faulting. 
The beds in the southern portion of the range have been folded 
long northwest-southeast axes into two great anticlines, whose con- 
ecting syncline is occupied by Pole Canyon. b Northward "the main 
rest of the range, between Tooele and Lewiston peaks, is the rem- 
ant of the flat arch of an anticlinal fold." ' The northern extension 
f this anticline may be identical with the anticline which crosses 
'ooele Canyon about two miles below its head. Thence the Car- 
A oniferous limestones, with the overlying siliceous series above 
escribed, strike eastward across Bingham Canyon until, at a point 
ear its mouth, they turn up steeply on edge and strike northward. 
i j 
"Emmons, S. F„ U. S. Geol. Expl. Fortieth Par., Vol. II, p. 440. 
blbid., p. 443. 
<*Ibid.,p. 443, 
