14 PAL^ONTOLOaY OF NEW JEKSEY. 



that the minute crystals with which both the loop and the interior of the 

 valves is coated bring it in contact with the valve, so that in breaking 

 away the shell to show the interior this part has been somewhat injured on 

 one side of each specimen. There is considerable difference observed in 

 the proportional form of the different parts of the loop in different speci- 

 mens, in the width of the band composing it, in the relative width between 

 the bands on the opposite sides of the center, and in the proportional length 

 of the transverse plate which connects the dorsal sides of the ribbon with 

 the median septum of that valve. Moreover, the ribbon in all cases where 

 seen is coated with minute crystals of lime, which gives it a much stronger 

 appearance than it has really possessed when in its normal condition. Tlie 

 loop in its general appearance presents much the same aspect that is seen 

 in that of Waldheimia australis of the present time, except that it has the 

 double attachment to the dorsal valve characteristic of the genus Terebra- 

 tella. The general shape of the shell externally had long ago decided 

 naturalists in referring the species to Terebratella^ but it has hitherto disap- 

 pointed all efforts to obtain a knowledge of its loop; but as it is now known 

 in several individuals, there can no longer be any doubt of its generic 

 relations. 



Formation and locality, — This is an abundant species at most of the 

 localities where the shell-bed of the Lower Green Marls is worked. At 

 Cream Ridge, New Jersey, it is extremely abundant; also at Middletown, 

 New Jersey. 



Terebratella Vanuxemi. 

 Plate I, Figs. 1-4. 



Terebratula Vanuxemi Lyell and Forbes. Quart. Jour. Geol. Soc, 1845, Yol. I, p. 62. 

 Terebratella Vanuxemi D'Orb. Prod. Pal., p. 259, Gabb, Synopsis Am. Gret. Brach., 



P. A. N. Sci., Phil., 1861, p. 18. Synop., p. 194. Meek, Gheck-list, p. 5. 



Geol. Surv. N. J., 1868, p. 724. 



Shell resembling T, plicata, Say, in size, form, and general characters, 

 varying only in the greater convexity of the valves, especially the dorsal 

 valve, and in the greater number of plications, which are less angular and 

 not so distinctly elevated or so distinctly marked. The ventral valve is 



