about the head of the Missouri, §c. 241 
ponding beds are shown in the valley below, we infer that they 
were accumulated long before the mountains were raised to 
their present height or perhaps during the gradual process of 
elevation. This is especially shown at the upper end of the 
Vind River valley. Passing over the Wind River mountains 
We again see them holding the same position on the western 
slope and possessing the same lithological characters. While 
the lignite beds on the west side of the ‘divide’ incline at a large 
angle, the more recent beds although in some places occupying 
the very crest of the mountains, seldom incline more than 3 
to 5 degrees, 
The most interesting additional facts which we have obtained 
Mountains to Willow Springs within ten miles of Cache la Pou- 
dre, that they also extend up the North Platte to the Box 
Elder creek, and even beyond are small outliers, showing that 
much has been removed by erosion. Passing over into the 
Laramie Plains we find at the source of the Box Elder and ex- 
pier over to the head of Bates Fork a large development of 
18 ‘lert} ‘ 
W 
Weh 
su 
‘ ticed 
Ch 
lignite Tertiary are often 
heighth by the upheaval of the mountains, but they do not in 
: aoe than 1° while north of Se lack Hills 
Along the Platte I have seen 
especially on La Bonte creek and about 
