12 EIGHTH ANNUAL REPORT OF 



capped with irregular pyramids, and extending upwards to a height 

 of from one to two hundred leet. "Viewed in the distance, these 

 rocky piles in their endless succession assume the appearance of mas- 

 sive architectural structures, with all the accessories of buttresses, turrets, 

 and tnpering spires." The portion of the surface thus excavated forms 

 a valley ot" ninety miles in length and thirty in breadth, which in its most 

 depressed portion is about three hundred feet below the surface of the 

 surrounding countr3^ So thickly are the natural towers studded over 

 the surface of this extraordinary region, that the traveller threads his 

 way through deep conhned passages, which resemble the narrow irre- 

 gular streets and lanes of some of the old towns of the continent of 

 Europe. At the foot of these columns, the remains of the ancient ani- 

 mals, which hved and breathed long before the advent of man upon 

 the face of the earth, are found in such abundance as to form of this 

 tract an extensive cemetery of vertebrated animals, rivalling, in the 

 variety of its extinct species, the celebrated beds of the Paris basin. 



This region having been brought to notice by a few fossil remains 

 procured through the agents of the American Fur Company, an ap- 

 propriation of about $200 for its exploration was made by the Smith- 

 sonian Institution to Mr. Thaddeus Culbertson, who was about to visit, 

 on account of his health, the sources of the Missouri. The specimens 

 of fossil remains which were thus procured, together with a collection 

 subsequently presented to the Institution by Capt. Stewart Van Vliet, 

 of the U. S. army, and several specimens kindly lent by Dr. Prout, of 

 Missouri, were referred to Dr. Leidy for examination. In addition to 

 these he had the use of a collection lent by Prof. O'Loghland, of Mis- 

 souri, specimens belonging to the Academy of Natural Sciences, Phila- 

 delphia, and a collection made by Dr. Evans, at the instigation of Dr. 

 D. Dale Owen, the whole embracing all the specimens which have yet 

 been brought to the east from the Bad Lands. The bones are com- 

 pletely petrified, and their cavities filled with silicious matter. They 

 are preserved in various degrees of integrity, some being beautifully 

 perfect and others broken and imperfect, the latter having been evi- 

 dently sul)jected to violence while imbedded in a soft mud. The ani- 

 mals belong to the classes mammalia and chelonia, or turtles. With a 

 single exception, all the species of mammalia belong to the great order 

 of ungulata or hoofed animals, of which there are seven species of four 

 genera, w-hicli belong to the ruminantia, or cud-chewing animals ; two 

 species of one genus belonging to the paradigitata ordinaria, or even- 

 toed animals ; one species of the solipedia, or solid-hoofed animals ; and 

 four species of three genera belonging to the imparidigitata orcUnaria, or 

 uneven-toed animals. 



The first specimen described belonged to a peculiar genus of rumi- 

 nants which, among recent animals, is more nearly allied to the musk, 

 and was probably hornless. The next is of a remarkable genus of 

 ungulata representing a type which occupies a position in the wide 

 physiological interval existing between recent ruminants and the anom- 

 alous fossil animal called the anoplotherium. Another genus is called 

 oreodon, and constitutes one of the links necessary to fill up the very 

 wide gap between existing ruminants and an exceedingly aberrant form 

 of the same family now extinct. Another organic relic is that of an 



