176 PALEONTOLOGY OF NEW JERSEY. 



One single specimen is somewhat shorter than common, in proportion to the 

 height of the spire, but this may only be an individual peculiaiity ; at least 

 the difference is not sufficiently marked to warrant any specific separation. 

 Figures of the best preserved individual have been given on PI. xxi of the 

 Middle Marl species for comparison with those from the Lower Marls. 



SCALARIID^. 



Genus CAVOSCALA, n. gen. 



Shell scalariform, thin in substance, with numerous round contiguous 

 volutions, which are crossed by oblique, raised varices. Surface cancellated, 

 axis broadly perforate, the umbilicus wide, angular on the margin and show- 

 ing the inner volutions. Base of body whorl margined by a broad flattened 

 band. Aperttire subcircular obliquely straightened on the inner side. Type 

 C. annulata, Morton's sp. Upper Cretaceous. 



The species upon which this genus is based is the only one known 

 Externally it resembless the living shell Scalaria pretiosa Linn., except in the 

 connected volutions; more numerous varices; cancellated surface and wide 

 umbilicus; the latter feature being Solarium-like in character, and also in 

 the broad flattened space extending from the margin of the umbilical cavity 

 to the outer basal portion of the whorl, where it terminates in an abrupt 

 shoulder which limits the next volution and forms a carinated suture. 

 The oblique varices and the fine transverse striae both cross this space and 

 are slightly visible in the umbilicus. The aperture is imperfect in all the 

 examples seen (seven), but of course the margin would be thickened and 

 bordered at each varix, so that it would present the appearance of a thick- 

 ened rim or peristome, but not larger or heavier than the other varices, as 

 in some forms of Scalaria. 



