NATURAL SCIENCES OF PHILADELPHIA. 



153 



forms of Fossil Mammalia among which were four new species belonging to the 

 family Rodentia,* a group not before discovered in this basin. A line oppor- 

 tunity was thus given to trace the connection of distant outliers on both sides 

 of the Missouri, with the main body of the Bad Lands at the head of White and 

 Shyenne rivers. 



I will now present a vertical section showing the order of superposition of 

 the diflerent beds at the various localities examined, premising, however, that 

 the thickness of the strata are all estimated. The section, therefore, cannot be 

 as perfect as could be desired, but may throw some light on the geology of that 

 interesting region. 



Vertical Section, shoicing the order of superposition of the different Beds of the 

 Bad Lands of White River, so far as determined. 



Subdivisions. 





Gray and greenish-gray sandstone, varying from 

 a Tcry fine compact structure to a conglomerate. 



Yellowish gray g.it, passing down into a yellow 

 and light yellow argillo-calcareous marl, with nu- 

 merous calcareous concretions and much crystalline 

 material, like t?ulphate of Baryta. Fossils: Hip- 

 parion, Merychippus, Stencofiber, &c. 



Grayish and light gray rather coarse-grained 

 sandstone, with much Sulphate of Alumina? dis- 

 seminated through it. 



Yellowish and flcsh-colored indurated argillo-cal- 

 careous bed, with tough argillo-calcareous concre- 

 tions, containing Tcstudo, Hipparion, Steneofiber, 

 Oreodon, Ehinoceros, &c. 



Yellow and light yellow calcareous marl, with 

 argillo-calcareous concretions and slabs of silicious 

 limestone, containing well preserved fresh-water 

 shells. 



Light gray silicious grit, sometimes forming a 

 compact fine grained sandstone. 



A reddish flesh-colored argillo-calcareous indu- 

 rated material, passing down into a gray clay, con- 

 taining concretionary sanasu,,.,3. sometimes an ag- 

 gregate of angular grains of quartz, underlaid by a 

 flesh-colored argillo-calcareous indurated stratum, 

 containing a profusion of Mammalian and Chelo- 

 nian remains. Turtle and Oreodon Bed. 



Light gray calcareous grit, passing down into 

 a stratum composed of an aggregate of rather 

 coarse granular quartz ; underlaid by an ash-co- 

 lored argillaceous indurated bed with a greenish 

 tinge. Titanotherium Bed. 



Gray and yellowish arenaceous clays and sand- 

 stones, sometimes weathering to a pink color ; con- 

 tains BeU.mnitella bulbosa. Nautilus Dekayi, Am- 

 monites placenta, A. lobatus, ScaphiUs Omradi, 

 Baculites grawHs, and great numbers of other 

 Marine Mollusca. 



Bijou II ills, Medicine 

 Hills, Eagle Nest Hills. 



Bijou Hills, Medicine 

 Hills, Eagle Nest Hills, and 

 numerous localities on south 

 side of White Hiver, also 

 at the head of Teton lliver. 



Along White Kiver val- 

 ley, on the south side. 



Seen along the White River 

 valley, on the south side. 



On the south side of White 

 River. Seen in its greatest 

 thickness at Pinao's Spring. 



been on both sides of 

 White River. Also at Ash 

 Grove Spring. 



Revealed on both sides of 

 White River and through- 

 out the main body of the 

 Bad L.ands. 



Best developed at the en- 

 trance of the Basin from 

 Bear Creek. Seen also in 

 the channel of White River. 



Immediately under the 

 Tertiary bed A at Bear 

 Creek. Seen also at Sage 

 Creek, head of Teton River, 

 Moreau Trading Post, Fox 

 Ridge. Butte aux Gres on 

 Mi-souri River, mouth of 

 Cannon Ball River. 



*See a paper by Prof. Leidy, in the Proceedings of the Philad. Academy, for April, 1857. 



1857.] 



