TRENTON LIMESTONE. 223 



Tlicrc is liulc difliciilty in identifying iliis curious and beautiful fossil, which is quite 

 abundant in the Trenton limestone. The ohlicjuely transverse ridges and nearly vertical 

 strife, which are always more promiiiont in the depressions tluui ui^on the ridges, are con- 

 stant in a large number of specimens. The shell at the angles seems to be slighlly folded 

 inward, jiroduciug a groove, wiiich interrupts tiie transverse ridges. It is but rarely that the 

 septa and siphuncle can be seen ; the latter is usually excentric, but in one specimen there 

 is an obscure appearance of a duplicate siphuncle. When the outer lamina of the shell only 

 is removed, the cast preserves the sharp transverse ridges, the longitudinal stria; being 

 obliterated. The entire cast is smooth, with a deep groove at the angles, and a shallow 

 one on the centre of each face of tlie pyramid. . . ' . 



Fig. 1 a. A specimen (natural size), with the apex broken off. 



Fig. I b. Another specimen, more abruptly acute. 



Fig. 1 c. Transverse section of a, near the apex, showing the septum and siphuncle. 



Fig. 1 d, e. Lateral and transverse view of a fragment, showing the convex septum. 



Fig. 1 /. A portion of the surface enlarged. 



Position and locality. In the central and higher part of the Trenton limestone at Middle- 

 ville, Jacksonburgh, Trenton Falls, and other places. 



2SS. 2. CONULARIA GRANULATA (n. 5/;.). 



Pl. LIX. Fig. -2. 



Conical or pyramidal ; specimen compressed, tapering rapidly to an acute point ; angles 

 marked by linear grooves or sulci ; surface marked by distinct transverse strife, which are 

 crossed by finer longitudinal ones, giving, under a magnifier, a granulated or papillose 

 appearance to the shell ; no septa or siphuncle visible. 



This species is quite distinctly marked ; and from the examination of several specimens, 

 I have no doubt of the propriety of its reference to the Genus Conularia. The specimen 

 figured is in soft shaly limestone, and presents no more than a thin laminar expansion. It 

 differs essentially from the last in the character of its markings, which are also much finer, 

 being scarcely visible to the naked eye. The surface is marked by longitudinal lines or 

 folds, which are probably due to the folding of the shell from pressiue. 



Fig. 2 a. A specimen nearly entire, giving the general form of this species. 

 Fig. 2 6. A portion of the surface enlarged. 



Position and locality. In the upper shaly portion of the Trenton limestone, associated 

 with Lingula, Orbicula, ^"c. 



289. 3. CONULARIA PAPILLATA (n.s/).). - " 



Pl. LIX. Figs. 3 a, ft. 

 Compare Conularia quadrisuUata, Daxman, Vet. Acad. Handlingar, 1S24, pag. 374, pl. 4, fig. 3. 



Pyramidal, sulcated at the angles, gradually diminishing towards the apex ; surface 



