INTRODUCTION. 13 



Section of Beds constituting the early tertiary {Eocene) of the Bad Lands {Mauvaises 

 Terres). — (Numbered in the descending order.) 



1. Ash-colored clay, cracking in the sun, containing silicious concretions 30 feet. 



2. Compact white limestone . . . . . . . . 3 " 



3. Light-gray marly limestone . . . . . . . . 8 " 



4. Light-gray indurated silicious clay (not effervescent) . . . 30 " 



5. Aggregate of small angular grains of quartz, or conglomerate, cemented 



by calcareous earth (slightly effervescent) . . . . . . 8 " 



6. Layer of quartz and chalcedony (probably only partial) . . 1 inch. 



7. Light-gray indurated silicious clay, similar to number 4, but more 

 calcareous, passing downwards into pale, flesh-colored, indurated, silicious, 

 marly, limestone (effervescent), turtle, and bone bed . , . .25 feet. 



8. White and light-gray calcareous grit (slightly effervescent) . . 15 " 



9. Similar aggregate to number 5, but coarser . . . . . 8 " 



10. Light-green, indurated, argillaceous stratum (slightly effervescent), 

 Titanotherium bed . . . . . . . . . , .20 feet. 



The extensive cemetery of eocene vertebrata in the Mauvaises Terres, or Bad 

 Lands, of Nebraska, was first brought to our notice in a communication entitled 

 Description of a Fossil Maxillary Bane of a Palwotherium, from near White River, 

 published by Hiram A. Prout, M. D., of St. Louis, in the American Journal of 

 Science and Arts, for 1847, page 248. 



Nearly at the same time, Mr. J. S. Phillips, when on a visit to Chambersburg, 

 Pen'nsylvania, observed in the possession of Dr. S. D. Culbertson, several remark- 

 able mammalian fossils, which had been sent as curiosities from the Bad Lands by 

 his nephew, Mr. Alexander Culbertson, of the American Fur Company. These 

 specimens, at the suggestion of the late distinguished Dr. S. G. Morton, were 

 obtained through Dr. John H. B. McClellan, a friend of Dr. Culbertson, and were 

 obligingly placed in my hands for examination. A description of them was pub- 

 lished in the Proceedings of the Academy of Natural Sciences, of Philadelphia, for 

 1847 and 1848; and they were afterwards presented by Alexander Culbertson 

 to the Academy. 



The attention of Dr. D. D. Owen having been directed to the interesting region 

 whence the fossils were obtained, he requested Dr. John Evans, an assistant in 

 the geological survey in which he was engaged, to pay it a visit. This gentleman 

 brought home a magnificent collection of fossils, which form the basis of one of 

 the chapters in the Report of Dr. Owen, before quoted.^ 



Through the instrumentality of Prof S. F. Baird, who from the first fully appre- 

 ciated the importance of a complete examination of the Mauvaises Terres and their 

 animal remains, Mr. Thaddeus A. Culbertson, under the auspices of the Smith- 



' Dr. J. Leidy's Memoir, p. 533, of the "Report of a Geolog. Surv. of Wise, etc." 



