56 Cretaceous. 



thickness of 100 feet. It is usuallj' soft and friable, and liable to dis- 

 integrate rapidly when exposed to the action of the weather. At Fort 

 Washita he found Ammonites several feet in diameter, and weighing 

 between 400 and 500 pounds. 



Dr. B. F. Shumard described Ostrea siibovata, Asturte Washttensis, 

 Cardium tnuUistriatum, now ProtocarcUa multistriata^ Tanopc&a tex- 

 ana, Terebratula choctaivensis, Globiconcha elevata, G. tumida, 

 Eulima suhfusiformis., Ammonites acuticarinatus, A. marcianus, He- 

 miaster elegans, now Toxaster elegans, and Hoi aster simplex. 



Dr. Leidj* described, from near Greenville, Clark count}^ Arkansas, 

 Brimosaurus grandis, now Cimoliasau7'us grandis. And Evans & Shu- 

 mard described, from Sage creek, Nebraska, Avicula linguiformis, A. 

 triangulai'is, Solarium Jlexistriatimi, now Margaritella fiexistriata., 

 Pholadomya elegantula^ and Rostellaria nehrascensis, now Anchura 

 nebrascensis; and from Fox Hills, Ilytilvs galpinqnus now Volsella 

 galpinana. 



In 1855, M. Tuomejt described, from Alabama and Mississippi, 

 Nautilus 07-biculatus, N. spillmani, JV. angulatus, Ammonites angus- 

 tus, A. binodosus, A. carinatus, A. magnijicus, A. ramosissimus, Tur- 

 rilites alternatus^ Turritella fastigiafa Fhorus umbilicatus, now En- 

 doptygma umbilicata, Voluta cancellata, V. fus>fo7-mis, V. jugosa, 

 V. spillmani., Fusus eufalensis, F. tui'riculns, Pyrula richardsoni, 

 now Pyropsis richardsorii^ P. trochifonnis, now Pyropsis trochiformis, 

 Cerithium nodosum., Teredo calamus., Panopwa cretacea, Pholadomya 

 tenua, Cmdium hemicyclus, Cucuiloea ungula, Inoceramus biformis, 

 I. inflatus, I. proximus, I. salebrosus., I. triangularis, Badiolites or- 

 mondi, It. aimesi, R. undulatus, Ichthiosarcolites cornutus, I. lorica- 

 tus, I. quadrangular is. 



T. A, Conrad]; described, from Dallas county, Miss., Baculites an- 

 nulatus, Hamites larvatus, H. rotundatus\ from Arkansas, Ancyloceras 

 approximans, and Cardium arkansasense, now Protocardia arkansas- 

 ensis; from Alabama, Caprina quadrata^ and from Texas, Bostellites 

 texanus, Turritella irrorata, Caprina occidentalism C. planata, JS/eithea 

 occidentalism Mactra texana, Exogyra fimbriata, and E. fragosa. 



Dr. Joseph Leidy§ described, from the greensand near Pemberton, 

 New Jerse^^, Pristis curvidens. 



* Proc. Acad. Nat. Sei., vol. 7. 

 t Proc. Acad. Nat. Sei., Tol. 7. 

 X Proc. Acad. Nat. Sci., vol. 7. 

 I Proc. Acad. Nat. Sci-, vol. 7. 



