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Show APPENWX E.<- GEOLOGY. 408 posite'of older date than the'tertiary w^ se observed. Of the specimens collected there is but a single individual' indicating the character of a marine formation. . From the condition of ( he bones . it may even be questioned whether the deposite containing them is not of post tertiary age. , " " ' ' * - The specimens from ' the vicinity of Eort Laramie. are all from limestone . of the carboniferous period. <- Sdme of the fossils are identical with species collected between the Missouri and the Big Blue, and, we can only suppose, from the great similarity of the specimen*, that it is a continuation of the same formation. ' From the dates marked upon the specimens, it is evident that this lime* atone, 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, are a feldspathic granite with little quartz or mica* The rocks in this locality art doubtless of me- ' tamorphic origin, probably rocks of Silurian age. - The specimens collected three days' ' march in advance of this place; cm the North Fork of the' Platte River, are shaly sandstone and thinly laminated * sandstones containing fossils. The fotoils are some brachiopods, - with other? similar to MonotiSj and we may presume from the described position'of the beds, and from the character; of the'fossils, that these beds are of devonian age. In the journal these beds are recorded as dipping at the rate of 15? to the north- east* , The specimens bearing the mark of July 24th, are precisely like those collected at Fort Laramie, and contain, the same species of fossils. On the same date were seen ( according to the journal) gray and red sandstones. - On the following day is recorded a' bed of coral, three or four feet thick, with Sigillaria and Catamites. The specimens of this ' date « ent to me are those of bituminous coal and others of soft shale, but 1 have been unable to distinguish any well- marked vegetable remains.. From the proximity of limestone of the age of the coal, and the record of sigillaria and . calamites occurring in the same connection, it may be presumed that this coal belongs to the true coal measures; and this locality is probably an exposure indicating the. existence of a great basin. This point itself and. the/ surrounding country are well worthy of a more extended examination, since the discovery of workable beds of coal in this region would be a. matter of national importance. The record of July 27th shows the occurrence of red shales and + |