Mesozoic and Coinozoic Geology and Palceontology. 23 



alis^ JSr. suhplana, JV. cancellafa, iV. planimarginata, Pectunculina 

 pari'ula, now Lhnopsis parvula, CuciiUwa cordata, now Idonearca 

 cordata, C. shumardi^ now /. shumardi, Mytilus attenuatus, now Vol- 

 sella attenuata^ Inoceramus pertenuis^ Pecten nebrascensis, Natica 

 suhcrassa^ now Lunatia subcrassa, JSTatica tuomeyana, now Vanikor- 

 opsis tiiomeyana, Panopoia occidentalism now Glycimeris occidentalism 

 Jfaclraformosa, M. ivarrenana, M. alta, Tellina subtortuosa, now 

 Thracia subtortuosa^ Cytherea owenana^ now Callista owenana, 

 Hettangia ameiHcana, now Tancredia amei^icana, Cardium speciosum, 

 and Jlytihis subarcuatus. 



Professor L. Harper* described, from the bed of the Tuscaloosa, or 

 Black Warrior river, near Erie, Greene county, Alabama, about twelve 

 miles above the confluence of the Tombigbee and Black Warrior rivers, 

 Ceratites americanus. 



Dr. Joseph Leidyf described, from the greensand of Burlington 

 county, New Jersey, Chelonia ornata, now Peritresius ornatus 

 Polygonodon vetus, Ischyrhiza m^Va, Edaphodon mirijicus, now 

 Ischyodus mii^ijicus ; from Neuse river, North Carolina, Ischyrhiza 

 antiqua ; and from the Upper Missouri, Cladocyclus occidentalis and 

 Enchodus shumardi. And from the Fort Union Group, at Long Lake, 

 Nebraska, Emys obscurus, now Compsemys obscurus, Compsemys victus, 

 and Mylognathus priscus ; from the lowest lignitic of Grand river, 

 Nebraska, Thespesius occidentalism and from the Bad Lands of Judith 

 River, Paloioscincus costatus, Trachodon mirabilis, Troodonformosus^ 

 Trionyx foveatus, Deinodon horridus^ now Amblysodon honndus, 

 Crocodilus humilis^ now Bottosaurus humilis, Lepidotus haydeni^ L. 

 occidentalis, and Ischyr other inm antiquum, now Ischyrosaarus 

 antiquus. 



In 1857, Arthur SchottJ described the Cretaceous basin of the Rio 

 Bravo. The main portion, from Las Moras to the vicinity of Rejuiosa, 

 forms a belt of 380 to 400 miles in width. The upper part of this belt 

 commences in the vicinit^^jof Las Moras, and terminates some few miles 

 above Laredo, a distance of about 200 miles, whilst the lower part be- 

 gins where the former ends, and reaches as far as the vicinity of Rey- 

 nosa, showing a width of about 340 miles. Both of these parts are 

 distinctl}^ characterized by strata of greensand (chloritic chalk), which 

 change, according to the amount of oxide of iron they contain, into 



'•'■ Proc. Acad. Nat. Sci., vol. 8. 

 t Proc. Acad. Nat. Sci., vol. 8. 

 t U. S. & Mex. Bound. Sur., vol. 1. 



