MARYLAND GEOLOGICAL SURVEY 299 



Occurrence. BEEKMANTOWN LIMESTONE (Ceratopea zone). Casts 

 and section of the shall may be observed at this horizon west of Hagers- 

 town, and also in several exposures east of Williamsport, Maryland. 

 Beekmantown of New York and Vermont. 



Collection. U. S. National Museum. 



MACLURITES OCEANUS (Billings) 

 Plate XXXV, Figs. 7, 8 



Maclurea oceana Billings, 1865, Pal. Fossils, vol. i, Geol. Surv. Canada, 

 p. 237, text fig. 223a, b. 



Description. Shell varying from 25 mm. to 100 mm. in diameter, 

 consisting of four or five, rather slender whorls with an umbilicus measur- 

 ing about half the whole width in the small specimens. Spire flat; the 

 outer edge narrowly rounded; the suture deeply impressed in the usual 

 specimens, casts of the interior, but compressed and thread-like when the 

 shell is preserved. Outer side of the body-whorl gently convex, and 

 sloping to the edge of the umbilicus at an angle of from 60 to 70 with 

 the plane of the flat side of the shell. Aperture a little less than half the 

 whole width of the shell in height. Edge of umbilicus acutely rounded ; 

 inner side of the whorls in the umbilicus gently convex, and somewhat 

 sloping with the edge exposed to the apex. Surface unknown, but most 

 probably finely striated. 



Occurrence. BEEKMANTOWN LIMESTONE (Turritoma zone). Natural 

 sections of this shell were noted in the exposures along the National High- 

 way east of Huyett, Maryland. Canadian of Newfoundland. 



Collection. U. S. National Museum. 



Genus CERATOPEA Ulrich 

 CERATOPEA KEITHI Ulrich 



Plate XXXVI, Fig. 15 



Operculum of f Maclurea Bassler, 1909, Bull. Geol. Surv. Virginia, vol. iia, 



pi. xx, fig. 3. 

 Ceratopea keithi Ulrich, 1911, Bull. Geol. Soc. Amer., vol. xxii, No. 3, p. 665. 



