LOWER HELDERBERG ROCKS. 
303 
Strophostylus globosus ( n. s.). 
Plate LY. Fig. 8. 
Shell globose. Spire short, obtuse : volutions three or four, rounded ex¬ 
teriorly, rapidly increasing in size, the last one symmetrically rounded 
and very ventricose, the upper margin of the lip extended at its junc¬ 
tion with the volution; aperture subcircular; suture distinctly cana¬ 
liculate. 
Surface marked by extremely fine threadlike undulating striae, and, in 
older shells, by faint revolving undulations. 
This species differs conspicuously from the S. elegans in its more depressed spire 
and more rotund form, as well as in the canaliculate suture and finer strise. The 
revolving undulations are too undefined to become a character of importance, unless 
in better preserved specimens than I possess : they are visible from reflection, on 
turning the specimen in the light. 
Fig. 8. A cast of the species, preserving a fragment of the shell along the suture. 
Since this plate was engraved, I have obtained specimens of this fossil, with the 
shell entire, from Becraft’s mountain, through the kindness of Mr. Wardle, for¬ 
merly of Stockport, Columbia county. 
Geological position and locality. In the shaly limestone of the Lower Heidelberg 
group, and in the compact beds of the same formation : BecrafVs mountain and 
Catskill. 
Stropliostylus olitusus (n. s.). 
Plate LXYIL Fig. 1 a , b. 
Shell subglobose; height a little greater than the width. Spire short 
obtuse, nearly flat above the second volution : volutions about four, 
very rapidly increasing in size, becoming very ventricose below the 
second one, and swelling out laterally; suture canaliculate, with a 
distinct ridge just outside the groove, from which the surface slopes 
abruptly to the general curvature of the volution : aperture round- 
ovate, contracted behind by the upper edge of the peristome, joining 
the volution below the middle. 
[ Palaeontology III.] 39 
