498 Systematic Paleontology 



Gyrodes abyssinus (Morton) Gabb 



Natica abyssina Morton, 1834, Syn. Org. Rem. Cret. Group, U. S., p. 49, pi. 



xiii, fig. 13. 

 Gyrodes abyssinis Gabb, 1876, Proc. Acad. Nat. Sci., Phila., p. 295. 

 Natica abyssina Whitfield, 1892, Mon. U. S. Geol. Survey, vol. xviii, p. 123, 



pi. xv, figs. 9-12. 

 Natica abyssina Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 21. 

 Gyrodes abyssina Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, 



p. 683, pi. lxxvii, figs. 7-9 (ex parte). 



Description. — "Shell with a flattened spire; suture channelled; body 

 whorl large, obtusely rounded ; umbilicus patulous ; aperture not expanded, 

 longitudinally elliptical. Diameter three-fourths of an inch." — Morton, 

 1834. 



Type Locality. — Prairie Bluff, Alabama. 



" Shell large, globose, with a flattened spire, the inner volutions of 

 which scarcely rise above the outer ones, and are only two and a half to 

 three in number; volutions rather ventricose and erect, ovate in a trans- 

 verse section; umbilicus large and open to near the apex of the shell; 

 aperture ovate, two-thirds as wide as long, and a little more convex on 

 the outside than on the inner margin, nearly equally rounded above and 

 below; suture well marked and deeply impressed." — Whitfield, 1892. 



Gyrodes abyssinus Morton has a meager representation in Maryland and 

 the specimens referable to it are in very poor condition. The species 

 seems about the same size as G. petrosus, but is much more erect than the 

 latter and does not exhibit any of the characteristic obliquity of G. petrosal. 

 It has, furthermore, a much more symmetrically rounded body, a deeper 

 sutural channel and a more rounded umbilical margin. 



Occurrence. — Monmouth Formation. Two miles west of Delaware 

 City on John Higgins farm, Delaware ; Bohemia Mills, Cecil County : 

 mouth of Turner's Creek, Kent County ; Brooks estate near Seat Pleasant. 

 Prince George's County, Maryland. 



Collections. — Maryland Geological Survey, Philadelphia yicademy of 

 Natural Sciences, New Jersey Geological Survey, U. S. National Museum. 



Outside Distribution. — Monmouth Formation. Navesink marl, New 

 Jersey. Eutaw Formation (Tombigbee sand member). Exogyra pon- 



