Marsh. ] 578 
COMMUNICATION ON THE DISCOVERY OF NEW ROCKY 
MOUNTAIN FOSSILS, 
Maver sy Pror. O. 0. Marsu 
At the meeting of the American Philosophical Society, Dec. 20, 1872. 
Professor O. C. Marsh, of Yale College, gave a brief account of some 
of the more important results of his paleontological researches in the 
Rocky Mountain region during the last three years. He had directed his 
attention mainly to the extinct vertebrates of the Cretaceous and Tertiary 
formations, and had obtained morc than 200 species new to science, about 
150 of which he had already described. Among the new types of fossil 
vertebrates thus discovered, were Pterodactyls, or Ornithosaurians, the 
first detected in this country. He had described three species of these 
from the Cretaceous of Kansas, all of gigantic size. Prof. Cope’ had 
subsequently redescribed two of the species in the Proceedings of this So- 
ciety (Vol. XII. p. 420), but the names Pterodactylus occidentalis, Marsh, 
and P. ingens, Marsh, given in the American Journal of Science (Vol. III. 
p. 241) had priority. A second and quite unexpected discovery of great 
interest was that of the Ichthyornide, or eretaceous birds with biconcave 
vertebrae, two species of which Prof. Marsh had recently described. A 
third discovery was that of fossil Cheiroptera, or Bats, not before ob- 
served in this country. The three known species were found in the 
Eocene of Wyoming. <A fourth new type was that of extinct Marsupials, 
also from the Eocene. A fifth discovery of great importance, was that 
of fossil Quadrumana, several genera and species of which he had found 
in the Eocene. Prof. Marsh stated that he had obtained indications of 
fossil Monkeys in this formation more than a year before, but had de- 
layed announcing the discovery until the evidence was conclusive. A 
sixth new type of animals, and perhaps the most interesting of all, were 
‘the gigantic Eocene Mammals, which he had recently assigned to the 
new order Dinocerea. These animals had limb bones somewhat like 
those of Proboscidians, as stated in the original description of the type 
species, Tinoceras anceps, Marsh. The skull, however, presents 2 most 
remarkable combination of characters. It is long and narrow, and sup- 
ported two, and possibly three, pairs of horns. The top of the skull was 
concave, and on its lateral and posterior margin there was an enormous 
crest. There were large decurved canine tusks resembling those of the Wal- 
rus, but noupperincisors. The six premolar and molar teeth were quite 
small. Several species of these remarkable animals have already been de- 
seribed, but at present they cannot all be distinguished with certainty. In 
addition to the type species already mentioned, Prof. Cope has given the 
name Lovolophodon semicinetus, to a single tooth, which may possibly be- 
long to this group. Dr. Leidy has described a characteristic specimen as 
Vintatherium robustum, and a canine tooth, apparently part of the same 
animal, under another name. The remarkable feature of the skull in 
this group was first indicated in the name Ténoceras, which the speaker 
had proposed for one of the genera. Prof. Cope subsequently proposed 
the name Hobdasileus, but was mistaken in regard to the main char- 
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