Geology. 127 
mens preserved, I have been able to recognize as extending for a con- 
siderable distance on the route between Turkey Creek and Big Sandy. 
Among the cretaceous fossils are a species of Pholadomya, and the 
ceramus, which is so abundant in numerous localities in this region. 
It is quite probable that these beds extend much farther, but I find no 
specimens in the collection; and the notes indicate that there are heav 
deposits of drift, which may have covered the formation below.” * 
“It would appear that the character of the country from near Fo 
4 continuation of the same formation. From the dates marked upon 
Specimens, it is evident that this limestone extends to some distance 
on the east and west of Fort Laramie. 
The specimens bearing date of July 19th, two days’ march northwest 
of Fort Laramie, (105° W.,) are a feldspathic granite with little quartz 
or mica. The rocks in this locality are doubtless of metamorphic ori- 
i 
.. Probably rocks of Silurian age. The specimens collected three 
Stone and thinly laminated sandstones containing fossils. The fossils 
ate some brachiopods, with others similar to Monotis, and we may 
Presume from the described position of the beds, and from the charac- 
ter of the fossils, that these beds are of Devonian age. In the journal 
beds are recorded as dipping at the rate of 15° to the northeast. 
he specimens bearing the mark of July 24th, (105° 50’ W.,) are 
Precisely like those collected at Fort Laramie, and contain the same 
ils. On the same date were seen (according to the jour- 
re gray and red sandstones. On the following day (near 106° W., 
7 recorded a bed of coal, three or four feet thick, with Sigil/aria and 
The specimens of this date sent to me are those of bitumin- 
si Coal and others of soft shale, but without any well-marked vegetable 
From the p 
cord of Sigillaria and Calamites oceurting in the same connection, it 
be Presumed that this coal belongs to the true coal measures ; and 
more extended 
Seal in thi region would be a matter of national importance. 
The record of July 27th (106° 45’ W.,) shows the occurrence of 
ep Shales and sandstones, which may be of the age of the coal, or 
he that formation.” * * * “From the Wind River Mountain 
Pt. Bridger (in 41° 18” N., 110° 32 W.,) the collections ar al éf 
+.» (ertiary, including many specimens of nautilus and others ma- 
Tee Shells.” +s West of Port Pall (43° N., 1124° W.,) are and 
of carboniferous age.” 
