MEMBERS OF THE AUSTIN SECTION. 321 



The molluscan species found in the Shoal creek limestone are sparsely 

 distributed and not abundant. During two years' residence in Austin 

 my wife and myself collected the following species, all but three of which 



are new 



^ 



Rotalia sp. Homomya, &p. nov. 



Textularia sp. . Panopxa, sp. nov. 



Three genera of conils, unstudied. Tnrrltella, sp. nov. 



Hemiaster calvani, Clark. Glohiconcha, sp. nov. 

 Alectryonia,pvoh£ih\y dilarlana of ljmna,rck.. Fasus, sp. nov. 



Exogyra, sp. nov. ' Anchura {'^.) , sp. nov. 



Voln roemeri, Hill. Pterocera shumardi, Hill. 



Pinna, sp. nov. Cerltkiuin (?j, sp. nov. 



Spondylus, sp. nov. Trochus, sp. nov. 



Cardium, sp. nov. Nautilus, sp. nov. 



Venus, sp. nov. Hoplites, sp. nov. 



These species collectively represent an entirel}^ new fauna in the 

 American Cretaceous. Its corals have not been found either in the beds 

 above or below; its echinodermata, especially the genus Hemiaster, are 

 found only in the upper series and not in the underlying Comanche. It 

 contains one alectryonate oyster provisionally referred to _0. dllavina, 

 which is found in the Comanche beneath, and one form which is clearly 

 an antecedent form of the Exogj/ra costata group of Upper Cretaceous 

 beds. It contains none of the Grypheate oysters or other moUusca which 

 characterize the Comanche. It has no Inocerami which specially mark 

 the Upper Cretaceous, and none of the Rudista) of the Lower. In fact, it 

 is a unique fauna, and represents south of the Brazos either deep-water 

 beds corresponding to the shallow Dakota north of that river or the time 

 represented by a land hiatus which immediately preceded the latter 

 epoch. As it also lies above beds which can with safety be called Gault 

 and below beds (Benton and Niobrara) which are Turonian, this would 

 l)robably place it near Cenomanian time. 



Exogyra arletina Beds. — These bedsf form a deposit of laminated green- 

 ish blue clay some eighty feet in thickness at Austin, where it has its 

 t^^pical occurrence. This clay outcrops immediateh^ beneath the Shoal 

 creek limestone coincident with its extent and rests upon the uppermost 

 band of the underlying limestone group — a paleontologic horizon which 

 I shall designate as the Kingend {Terebratida) loacoensuX bed. 



* The descriptions of this fauna will be published as nearly sinnultaneously with this paper as 

 possible. The type specimens are in the Museum of Johns Hopkins University, and are being 

 studied by Professor W. B. Clark. 



t Originally defined by Shumard. Trans. Acad. Sci., St. Louis, vol. 1, pp. 584, 586. 



J There are but two brachiopod forms in the Comanche, both of which have been examined by 

 Mr Charles Schuchert, who reports that they belong to the genus Kingena, hitherto not reported 

 in America. Each of these occurs in two well defined stratigraphic horizons— the one here defined, 

 and the otlier in the Duck creek beds of Denlson. 



XLIV— Bull, Gkoi-. Soc. Am., Vol. 5, 1893. 



