OF THE UPPER MISSOURI. 3 
tinct formations. No. 1, he seems to have referred to the Carboniferous system. As he 
did not go above Fort Pierre he saw nothing of No. 5, though he obtained some of its cha- 
racteristic fossils, which may have been presented to him by members of the American Fur 
Company. 
Mr. Edward Harris, who accompanied Mr. Audubon to the mouth of the Yellowstone 
in 1848, was instructed by the Academy of Natural Sciences at Philadelphia to make 
some observations on the geology of that unknown region. ‘This communication to the 
Academy on his return was very interesting, and contained many important facts, and 
from his notes and collections the committee were able to arrive at still more important 
conclusions. The committee, consisting of Professors Rogers, Morton, and Johnson, re- 
ported that they found incontestable proofs of a freshwater formation in that region. 
From one locality Mr. Harris obtained a specimen of “ brown ferruginous rock, containing 
three or four species of freshwater univalve shells of the genera Limnea, Planorbis, &e. 
One of the species of Planorbis it is conjectured may be a form extinct, but the mutilated 
condition of the specimen prohibits a positive opinion. ‘This bed of clay also contains 
leaves of deciduous trees, bearing a close resemblance to those of the Beech.” 
At various times, specimens of Mammalian remains were brought in by gentlemen 
connected with the American Fur Company, indicating the existence of an interesting 
deposit on White river; the first account of which was published by Dr. H. A. Prout of 
St. Louis, in the American Journal of Science, 1847. 
In 1849, Dr. John Evans, one of the assistants in the geological survey of the Chippeway 
Land District, under the direction of Dr. D. D. Owen, was sent by that gentleman on an 
expedition to the Mauvaises Terres of White river. He there secured a fine collection 
of Mammalian and Chelonian remains, which were investigated by Professor Leidy of 
Philadelphia. He also collected many interesting Cretaceous fossils, which were described 
by Dr. Owen, and published in his final report in 1852. Dr. Evans’s observations embrac- 
ing a section of the Bad Lands, together with a description of their physical features, were - 
also published in this report. 
In the following year Mr. Thaddeus A. Culbertson visited the Upper Missouri country 
under the auspices of the Smithsonian Institution, during which expedition he collected 
some interesting vertebrate remains from the White river formations. He also ascended 
the Missouri on the Fur Company’s boat, to a point above Fort Union, noting the cha- 
racter of the surface of the country, and the occurrence of lignite beds at various localities. 
In the spring of 1853, Dr. Evans again visited this country incidentally, while on his 
way to Oregon Territory, in the geological survey of which he was engaged, under the 
patronage of the General Government. During this expedition he made another extensive 
collection of vertebrate remains and some freshwater Mollusca at the Bad Lands of White 
