MUSEUM OF COMPARATIVE ZOOLOGY. 59 
conspicuous by the presence of some of the most common species of the 
Miocene, even of some species still living at the present epoch, as seen 
above, which had not been observed at any of the localities of the 
Eastern States where the specimens I had for my first examination 
had been found. These species, Populus arctica, P. Nebrascensis, P. 
crenata, Platanus Guillelne, P. aceroides, Aralia notata or Platanus 
nobilis, Tilia antiqua, Negundo decurrens, closely allied if not a mere 
variety of Negundo triloba, Carya antiquorum, Amelanchier typica, all 
Miocene species, now found in the coliection made at Golden, show an 
- intimate relation between the flora of Golden and that of Fort Union, 
which by new discoveries will probably become more apparent between 
the different localities of the Laramie Group, and complete the evidence 
of the unity of the characters of the flora. 
The group of plants described here afford a remarkable evidence of 
the distribution of vegetable remains under peculiar circumstances. 
The specimens were obtained from a locality which has been visited 
many times by members of the U. S. Geological Surveys of the Terri- 
tories, often by Mr. Lakes himself, and twice by myself. Nevertheless, 
not a single specimen of Populus Nebrascensis, nor of Platanus Guillelme, 
had been found there before ; yet in a locality at the same horizon and 
at a very short distance, a few rods only, as far as I know, from the ex- 
cavations formerly made, specimens of these two species and their varie- 
ties have been obtained in such abundance that they constitute nearly 
one half of the collection. This proves that the mode of distribution of 
the vegetable remains results in some cases from the deposition of the 
fragments at the place where the trees have grown, not from transporta- 
tion by water. Though the specimens of Golden are very fragmentary, 
they are generally flat upon the surface of shale apparently composed 
of muddy deposits, seemingly progressing in their formation while the 
leaves were falling from trees grown either around woody swamps or on 
the borders of shallow lakes. 
Recent explorations have brought on the discovery of a large number 
of localities rich in remains of fossil plants, over the whole extent of the 
Great Lignitic. The flora of the Laramie Group, which now counts 
only 250 species, will therefore probably soon become better known, and 
by the greatly increased number of its species will take an important 
place in the history of the ancient vegetation of the earth. 
