GASTEROPODA OP THE LOWER GREEN MARLS: 147 



and only a small- portion of the shell substance remains. The spiral lines 

 are usually distinct, but the minute transverse lines of growth which ought 

 to mark the surface are only occasionally seen. The species has apparently 

 reached a pretty large size, one individual having a length of considerably 

 more than 3 inches, and is imperfect at each end. Dr. Morton's figure 

 given in the Synopsis is more rapidly tapering tnau any of the examples I 

 have seen. Among the specimens borrowed from the collection at Phila- 

 delphia there is a fragment which I supposed to be the one used and figured 

 by Dr. Morton. It is compressed to less than one-half of its original diam- 

 eter and is probably correspondingly increased in its rate of expansion, which 

 will in part account for the outline of his figure. The specimen is much 

 injured and is probably less perfect than when Dr. Morton used it. I have 

 attempted to give a figure of it as it now is as a record of its existence and 

 condition, as it will in all probability entirely decompose in a few years. 



■ Formation and locality: Dr. Morton gives only New Jersey and Alabama 

 as localities. His New Jersey example is probably from Upper Freehold, 

 from whence I have several examples. Othei's are from near New Egypt, 

 Tinton Falls, J. Banks's pits near Marshall ville, and from J. S. Cook's beds 

 near Tinton Falls, New Jersey; all from the Lower Marls. 



Genus LAXISPIRA Gabb. 

 Proc. Acad. Nat. Sci., Phila., 1876, p. 301, PL xvii, Figs. 6, 7. 



Mr. Gabb's description of this genus is as follows: "Shell spiral, dextral, 

 whorls with a circular cross section, few in number, and so rapidly descend- 

 ing as to form an open spiral; aperture simple, lips thin." 



His remarks on this genus are as follows, given in full: 



A curious genus, the relations of which are not clear to me. I propose it to 

 receive some shells which have been long known as internal casts in the marls of 

 New Jersey, but of which the surface was unknown until quite recently. In gen- 

 eral form they might be compared to a partially uncoiled Turritella. From that 

 genus they differ, however, in the whorls not being in contact, and from Vernietus 

 and the allied genera in being regular spirals, but not having the apex either tur- 

 ritelloid or attached. Another analogy, though perhaps only one of external 

 resemblance, might be adduced in such shells as Euomphalus circinalis Goldf., or 

 in some of the Delphinulas. 



