237 



A single specimen of an operculum was found in the same piece of 

 limestone, with several shells of this species. It is a flat thin plate, with 

 a muscular process, as in M. Logani. 



The edge of the umbilicus is exhibited in more than fifty specimens, 

 and in all it bears a sort of a rounded band, which is beautifully crenula- 

 lated transversely, as in most of the species of Solarium. 



The inner whorls of the spire are sometimes a little elevated above the 

 others. The upper side of the whorls is quite flat, when the shell is 

 preserved, and usually so in the casts of the interior, but sometimes 

 rounded. 



Width of a specimen of the average size 15 lines ; height 7 lines ; 

 width of the umbilicus 4 lines, varying from one-fourth to one-third the 

 whole width of the shell. 



Numerous small silicified specimens of this species were collected at 

 Table Head and Point Rich, where it appears to range through a thick- 

 ness of about 900 feet. 



Closely allied to M. oceana, but differs in having the edge of the 

 umbilicus acute and crenulated instead of narrowly rounded ; in having 

 the inner side of the whorl in the umbilicus flat instead of convex ; the 

 umbilicus also is narrower, and the operculum thin, with a well developed 

 muscular process. The lowest strata in which it has been found are 

 about 300 feet higher than the highest holding M. oceana. 



Locality and Formation. I, K, L, M, N, Table Head and Point Rich, 

 Newfoundland ; Quebec group. 



Collector. J. Richardson. 



MACLUREA OCEANA. (N. sp.) 



a 6 



Fig. 223. 

 Fig. 223. Maclurea oceana. a, the spire ; b, front view. 



Description. Shell from one to four inches across ; whorls four or five, 

 rather slender ; umbilicus about half the whole width (in small specimens ; 

 it has not been seen in those of large size). Spire flat ; the outer edge 

 narrowly rounded ; the suture compressed and thread-like when the shel 



