Geoscience Reference
In-Depth Information
Medicine Bow
Mountains
Feet above
sea level
Laramie
Range
12,000
Snowy Range
Laramie
Basin
7,000
Mesozoic
Paleozoic
West
East
0
3
0 miles
Scale
Feet above
sea level
Laramie Range
Laramie Basin
8,600
Qa
Qa
Qa
7,200
Qa
Ku
Pf
Ps
Jm
West
East
0
4 miles
Scale
EXPLANATION
Quaternary
Alluvial deposits
Mesozoic
Cretaceous formations, undivided
Morrison Formation (Jurassic)
Chugwater Formation and Jelm Formation (Triassic)
Paleozoic
Forelle Limestone (Permian)
Satanka Shale (Permian)
Casper Formation (Pennsylvanian-Permian)
Precambrian
Fig. 17.2. Geologic structure of the Laramie Basin. the top dia-
gram is a generalized cross section of the entire basin, showing
the underlying sedimentary strata and the fault that was im-
portant in the formation of the Medicine Bow Mountains. the
bottom diagram shows more detail in the vicinity of Laramie.
the abundance of Quaternary alluvial deposits on the surface
is indicated, as is the thickness of the casper Formation—an
important aquifer in the basin. the Forelle Limestone forms a
prominent ridge east of Laramie; the colorful casper Forma-
tion is exposed south of Laramie in the vicinity of Red Buttes
and chimney Rock. Figure 2.3 illustrates the geologic develop-
ment of the basin; a geologic time chart is presented in fig. 2.1.
Adapted from Mears et al. (1986).
Granite
Undivided metamorphic rocks
Fault, arrow indicates relative direction of movement
Shear zone
uninished cabin was found near Sybille . 7 it would be
good if more could be learned about his life, consider-
ing that so many places bear his name—Laramie Peak,
Laramie River, Laramie city, Fort Laramie along the
north Platte River, and Laramie county to the east of
Albany county.
in 1825, about 5 years after La Ramie arrived, the fur
baron General William Ashley led an expedition across
the basin. the general wrote in his journal that the val-
ley and mountains were “enlivened by innumerable
herds of buffalo, antelope [pronghorn] and mountain
sheep.” He also wrote about the many small streams that
were “bordered with a thin growth of small willows and
richly stocked with beaver.” narrowleaf cottonwood
also was observed. Another explorer, e. Willard Smith,
entered the valley from the south in 1840, observing
“a great many buffalo every day as we passed along.”
in 1843 captain John c. Fremont's party was in the
basin with Kit carson, killing a pronghorn near tie
Siding and camping along the Laramie River. As they
 
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