AET. 10 CRETACEOUS FAUNAS OF THE CAEOLINAS STEPH.ENSOK 9 



tiny mamelon can be detected on some of the tubercles; the base is 

 covered with larger tubercles which vary considerably in size on 

 different parts of the surface. 



The apical system is situated slightly forward from the center; 

 the madreporite is large and somewhat elongated; the other genital 

 plates are small and close to the madreporite and bear pores. The 

 ocular plates are minute and can not be clearly seen. 



The peristome, is situated slightly in front of the center of the 

 broadly concave base, and includes five prominent, rather narrow 

 oral lobes whose tips do not approach so close to the center as in the 

 preceding species and whose separating ambulacral furrows are not 

 so narrow; the mouth is therefore somewhat more open. Tiny 

 tubercles can be detected on the walls of the ambulacral furrows of 

 the better preserved specimens. 



The periproct is circular, moderately large, and is situated well 

 above the base at the anterior end of a broad shallow sulcus which 

 extends downward without change of width to the ambitus. 



Remarks. — This species may be the same as the one described by 

 Emmons ^ under the name Gonioclypeus subangulatus^ but the type 

 of that species is probably lost, and the description and figures are 

 inadequate for identification. Clark ^ referred Emmons's species 

 questionably to Cassidulus and expressed the opinion that it was a 

 Cretaceous species. The type was obtained by Emmons from a 

 sample of marl from Craven County, N. C, sent to him by W. B. 

 Wadsworth, whose address was Core Creek post office (now aban- 

 doned). This marl was regarded as of Eocene age. Core Creek 

 is a small tributary of Neuse River in the northwestern part of 

 Craven County, in an area now mapped as Eocene, but the marl pit 

 from which the sample was taken may have been sunk deep enough 

 to cut through the Eocene into the upper part of the underlying 

 Peedee formation of the Cretaceous. 



This species is closely allied to Gassidvlus subquadratus Conrad, 

 the type of which was found by Dr. W. Spillman in the Ripley 

 formation, Exogyra costata zone (Upper Cretaceous), in Tippah 

 County, Miss., and is now in the Academy of Natural Sciences of 

 Philadelphia. Compared with Conrad's species, the North Carolina 

 species is smaller, flatter, and less broadly domed, the pore pairs are 

 a little more closely spaced, and the madreporite is more elongated. 



The specimen figured by Clark ^ as typical of C. subquadratus 

 Gabb, compared with the type, is not a strictly typical specimen; 



8 Emmons, Bbenezer, "Agriculture of the eastern counties ; together with descriptions 

 of the fossils of the marl beds." Report of the North Carolina Geol. Survey, p. 309, 

 figs. 242, 243, 1858. 



■^ Clark, W. B., The M'esozoic Echinodermata [of the United States] : U. S. Geol. 

 Survey Mon. 54, p. 81, 1915. 



8 Idem, pi. 31, figs. 2ar-g, 1915. 



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