NATURAL SCIENCES OF PHILADELPHIA. 



419 



General Section of the Cretaceous Rocks of Nebraska. 



Divisions and Subdivisions. 



Localities. 



* * 



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Gray, ferruginous and yellowish saudstone and 

 arenaceous clays, cuntuiniug Betemnittlla bulbosa, 

 Nautilus Dekayi, Ammonites placenta, A. tobatus, 

 Scaphites Conradi, S. Nicollttli, Baculites gran- 

 dis, Busycon Batrdi, Fusus C ulhertsoni, F. New- 

 berryi, Aporrhais Americana, Pseudo-buccinum 

 Nebrascensis, Mactra Warrtnana, Cardium sub- 

 quadratum, and a great number of other mol- 

 luscous fossils, together with bones of Mosasaurus 

 Missouriensis, &.c. 



Fox Hills, near Mo- 

 reau River, near 

 Long Lake above Fort 

 Fieri e. Along base 

 Big Horn Mountains, 

 and on North and 

 South i'latte Rivers. 



OS 





Dark gray and bluish plasiic clays, containing 

 near the upper part, Nautilus Dekayi, Ammonites 

 placenta, Baculites ovatus, B. compressus, Sca- 

 pldtes rtodosus, Dentalium gracile, Crassatella 

 Eoa?isi, Cucullaia Nebrascensis, Inoceramus Sa 

 gensis, I. Nebrascensis, I. Vanuxemi, Bones of Mo- 

 sasaurus Missouriensis, &c, &c, &c. 



Middle zone nearly barren of fossils. 



Lower fossiliferous zone, containing Ammonites 

 complexes, Baculites ovatus, B. compressus, Heli- 

 coceras Mortoni, II. toi turn, H. umbilicatum, H. 

 cocldeatum, liychnctras Mortoni, Fusus vinculum, 

 Anisomyon borealis, Amauropsis paludiniformis, 

 Inoceramus sublaevus, I. teuuilineatus, bones of 

 Mosasaurus Missouriensis. &c. 



Dark bed of very flue unctuous clay, containing 

 much carbonaceous matter, with veins aud seams 

 of gypsum, misses suiphuret iron aud numerous 

 small scales fishes. Local ; filling depressions in 

 the bed below. 



Sage Creek, Chey- 

 enne River and on 

 White River above 

 the Mauvaises Terres. 



Fort Pierre and out 

 to Bad Lands, down 

 the Missouri on the 

 high country to (Jreat 

 Bend. 



Great Bend of the 

 Missouri, below Fort 

 Pierre. 



Near Bijou Hill, on 

 the Mirsouri. 



Lead gray calcareous mail, weathering to a 

 yellowish or whitish chalky appearance above. 

 Containing large scales and other lemaius of 

 fishes, and numerous species of O strea conyesta at- 

 tached to fragments of Inoceramus. Passing 

 down into light, yellowish and whitish limestone, 

 containing great numbers of Inoceramus pro- 

 blematicus, I. pseudo-mytiluides , I. aviculoides and 

 Ostrea conge.sta, fish scales, &c. 



J. 



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6" 



Bluffs along the 

 Missouri below the 

 Great Bend, to the 

 vicinity of Big Sioux 

 River ; also below 

 there on the tops of 

 the hills. 



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Dark gray laminated clays, sometimes alternat- 

 ing near the upper part with seams ana layers 

 of soft gray aud light-colored limestone. Inoce- 

 ramus problematic us, I. tcniriroslratus, I. latus f I. 

 fragilis, Ostrea congesta, Venilia Mortoni, Pliola- 

 domya papyracea, Ammonites Mullani, A.percari- 

 natus, A. vesper tinus* Scaphites Warreni, S.larvce- 

 formis. S. ventricosus, S'. vermi/ormis, Nautilus 

 elegans t he. 



Extensively devel- 

 oped near I ort Ben- 

 ton on the Upper 

 Missouri; also along 

 the latter, from ten 

 miles above James 

 River to Big Sioux 

 River, and along the 

 eastern slope of the 

 Rocky Mountains, as 

 well as at the Black 

 Hills. 



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Yellowish, reddish and occasionally white sand- 

 stone, with at places, alternations of various 

 colored clays and beds and seams of impure lig- 

 nite. Also silicified wood, and great numbers of 

 leaves of the higher types of dicotyledonous 

 trees: with casts of Pharellaf Dakotensis, Axir 

 naea Siouxensis, and Cyprina arenarea. 



Hills bck of the 

 town of Dakota ; also 

 extensively developed 

 in the surrounding 

 country in Dakota 

 County below the 

 mouth of Big Sioux 

 Kiver, thence ex- 

 tending southward 

 into Northeastern 

 Kansas and beyond. 



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*This is A. Texanus of Roemer. It is on the authority of Mr. Gabb that ii is here 

 regarded as identical with A. vesperlinus of Morton. We should never have suspected 

 this from Dr. Morton's figure, but Mr. Gabb assures us that after a careful comparison 

 of Dr Morton's specimen, he can see no difference. 



1861.] 



