Geology. 281 
Nebraska Territory, collected during the Geological Survey u 
the direction of Dr. D. D. Owen; by Jos. Lerpy, M.D. From D. D 
Owen’s Report of a Geological Survey of Western Iowa, and Minne- 
sota, &c. Philadelphia, 1852. 4°.—This memoir affords another evi- 
16. Description of the remains of extinct Mammalia and Chelonia from 
} j nder 
North America, and may furnish many more interesting extinct forms. 
The mammalia described by Dr. Leidy belong to his new genera 
Oreodon, Archzotherium, and Eucrotaphus, and to the genera Palzo- 
therium, Rhinoceros, and Machairodus, he and Dr. Owen have added 
new species, all of which are beautifully illustrated. The reptiles, 
four in number, belong all to the’ genus Testudo proper. Besides the 
species described in full, there is at the close of this paper a list of five 
other species mentioned elsewhere before. shee 
17. Memoir of the extinct species of American Ox; by Jos. Leipy, 
M.D. From the Smithsonian Contributions to Knowledge. Vol. v.— 
This is a very valuable contribution to the natural history of the fossil 
species of Ox found in North America. The author refers them to two 
genera: Ist, Bison, the type of which is our Buffalo, and, 2d, a new 
The nearest approach to a natural classification has been propose 
n 
Barrand 
rows, such as Virgularia and Sertularia. I believe, however, that their 
true position is neither among Polyps, nor among Acalephe, to which 
class the Hydroid polyps must now be referred, but among Molluscs, in 
the class of Acephala, in the order of Bryozoa, of which many are found 
Srconp Seats, Vol: XVI, No. 47.—Sept., 1853. 36 
