Maryland Geological Survey 485 



Laxispira lumbricalis Gabb 



Laxispira lumbricalis Gabb, 1876, Proc. Acad. Nat. Sci., Phila., p. 301, pi. 



xvii, figs. 6, 7. 

 Laxispira lumbricalis Tryon, 1883, Struct, and Syst. Conch., vol. ii. p. 309, 



pi. lxxix, fig. 14. 

 Laxispira lumbricalis Whitfield, 1892, Mon. U. S. Geol. Survey, vol. xviii, 



p. 148, pi. xviii, fig. 25. 

 Laxispira lumbricalis Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 22. 

 Laxispira lumbricalis Weller, 1907, Geol. Survey of New Jersey, Pal., vol. 



iv, p. 706, pi. lxxxi, figs. 1, 2. 



Description. — " Shell with a circular cross-section, whorls about as far 

 apart as the diameter of the whorls, three or four in number ; surface 

 marked by numerous small, closely placed revolving ribs." — Gabb, 1870. 



Type Locality. — Haddonfield, New Jersey. 



" The dimensions of a large specimen, an internal east, are : Height 

 29 mm., maximum diameter 12.5 mm., apical angle about 28°, number of 

 volutions about 4|, height of aperture 8.5 mm., width of aperture 6.3 mm. 

 Shell forming an open spiral, in which the volutions are not in contact, 

 the sutural space in the casts being nearly as wide as the diameter of the 

 volutions. Cross-section of the volutions nearly circular, except in the 

 outer volution of mature shells, in which, near the aperture, the shell is 

 slightly compressed, making the aperture higher than it is wide and 

 straighter on the inner than on the outer lip. Surface of the shell marked 

 with fine, raised, revolving lines, from two to four of which occupy the 

 space of 1 mm., and by transverse lines of growth." — Weller, 1907. 



The species is so well characterized by the lirated loose coil that even 

 the fragments which represent the species in Delaware can be determined 

 with assurance. 



Occurrence. — Matawan Formation. Post 218, Post 105, Chesapeake 

 and Delaware Canal, Delaware. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

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



Outside Distribution. — Matawan Formation. Merehantville clay marl, 

 Woodbury clay, New Jersey. Ripley Formation. Exogyra costata zone, 

 Union and Tippah counties, Mississippi. 



