436 J. M. BOUTWELL 
GENERAL GEOGRAPHY 
The Wasatch Mountains, in their middle course, lie in the eastern 
part of Utah. They are a lofty, rugged range trending northerly 
and southerly between the Great Basin on the west and the mountain- 
ous plateau regions on the east. From a ragged serrate divide on 
sharp, ledgy peaks 10,000 to 11,000 feet high, the western slopes fall 
off abruptly 5,000 to 6,000 feet by a wall-like front of striking steep- 
ness to the desert below; while the eastern slope, in marked contrast, 
gives way gradually to upland ranges, plateaus, and high-lying mead- 
ows. ‘This unsymmetrical range may thus be compared to a mam- 
moth step several thousand feet in height from the Great Basin on the 
west to the highlands which extend from its upward portion east- 
ward: These western slopes are interrupted by deep, narrow, rock- 
walled canyons, through which the drainage from the uplands and 
parks escapes westward to the desert. The portions of the western 
wall which lie between these canyons show a marked type of dis- 
section which is characterized by ravines that rise from the level of the 
desert with steep sides and bottoms, and fork symmetrically upstream 
repeatedly. ‘The topography in both its larger and smaller features, 
showing rugged, precipitousslopes, deep, narrow canyons withungraded 
bottoms and side cataracts, is indicative of the youth of this range. 
GENERAL GEOLOGY 
The rocks which form the range are sedimentary, metamorphic, 
and igneous. The Wasatch sediments, as concisely described by 
King,’ are made up of four great divisions, a purely detrital series 
of Cambrian age, a great limestone extending from Cambrian to the 
top of the lower Coal Measures, a body of pure siliceous detritus of 
upper Carboniferous age, and a fourth body of limestone of upper 
Coal Measure age. ‘The metamorphic rocks include the early region- 
ally metamorphosed sediments and the locally altered or contact 
metamorphosed rocks. Beyond the fact that these great metamorphic 
series are pre-Cambrian, their age is unproved, though they are known 
to be the oldest rocks in the Wasatch. The igneous rocks include sev- 
eral large granitic and porphyritic intrusives and extensive flows. 
t Clarence King, Geological Exploration of the Fortieth Parallel Survey, Vol. I, 
PP. 100, Iot. 
