812 The American Naturalist. [September, 
of the Geological Survey of Texas of 1892, which explored the eastern 
border of the Staked Plain from the Texas Pacific R. R. on the south 
to the Denver and Fort Worth road on the north. The party was 
under the direction of Mr. Wm. F. Cummins, who was accompanied 
by Professor Cope. They examined exposures of the beds of the Trias, 
and of Cenozoic beds of the terranes Loup Fork, Blanco and Equus, 
together with a bed between the Loup Fork and Blanco. The number 
of species obtained from each of these horizons is as follows: Trias, 7 
Loup Fork, 17; Blanco, 16; Equus, 10; bed between Loup Fork and 
Blanco, 8; total, 58. Of these, eleven were not regarded as determin- 
able. Of the forty-seven species determined, the following were first 
discovered by the explorations of the geological survey ; Trias, 4; Loup 
Fork, 3; intercalated bed, 3 ; Blanco, 14; Equus, 5: total, 29. Among 
the results we find the following. The establishment of a peculiar 
species of Episcoposaurus from the Trias. The discovery of a Tetra- 
belodon, not previously known to be of Loup Fork age, allied to the 
T. serridens. The determination of the range of variation of the den- 
tition of the Protohippus placidus, and the determination of the tem- 
porary dentition of Protohippus and Hippotherium. The more impor- 
tant results obtained from the bed intercalated above the Loup Fork 
is the finding of a new species of Protohippus, Hippidium, and Equus, 
each; the last named allied to the E. minutus; the discovery of new 
genera of Mustelidae and Hyaenidae from the Blanco bed; the 
rehabilitation of the Tetrabelodon shepardii Leidy hitherto known from 
a single molar tooth; the species being found to resemble in some 
respects the genus Dinotherium. Also the determination of three other 
mastodons from the Blanco bed, and of a large new species of camel 
of the genus Pliauchenia; the discovery of a true horse (Equus 
minutus Cope) not larger than a sheep. The Equus bed yielded a huge 
Mylodon, represented by fragments only, four species of horses, and 
three of camels of the genus Holomeniscus, two of the last named 
being new to science 
Twenty-three plates illustrate the report, which add much to its value, 
although little can be said in favor of their artistic merits, as they are 
printed on ordinary paper. 
