THE KIMMSWICK AND PLATTIN LIMESTONES 
211 
their number varies from 7 to 9, and 11 occasionally are found. 
The transverse rows of granules tend to be supported by low 
transverse wrinkles or striae, but the intermediate grooves 
never are sharply defined and the wrinkles or striae often are 
obsolete. In the latter case the granules appear arranged in 
rectangularly intersecting rows on otherwise nearly smooth sur- 
faces. On some fragments, numerous low parallel wrinkles 
more or less connect the granules in a diagonal, not in a vertical, 
direction, somewhat as in Conularia cayuga as figured by Hall 
(Pal. New York, 5, pt. 2, 1879, pi. 34, fig. 5) from the Hamilton 
group of New York. 
From the city quarry, one mile southeast of New London, in 
the upper part of the Plattin limestone. 
27. Hyolithes baconi Whitfield 
Plate XXI, figs. 10 A, B, 11; plate XXII, figs. 10, 11 
Apical angle 20 degrees. Top of shell 9 mm. in width. Cross- 
section somewhat triangular, with one side flattened and the 
opposite side convex, the dorso-ventral diameter at the top of 
the shell being 2.5 mm. in the shell here described. The small 
size of this diameter may be due in part to compression. The 
shell is striated transversely, the direction of these striae being 
almost directly transverse on the convex side of the shell, while 
on the flattened side they curve distinctly upward. 
In one specimen (fig. II) the median part of the convex side is 
slightly more convex than the lateral parts of this side, and is 
separated from the latter on each side by a slightly concave 
area. The lateral margins are narrowly rounded. Of the trans- 
verse striae 14 occupy a length of 3 mm. at the larger end of 
the shell, preceded by 15 in the same distance at midlength, 
increasing still farther in number toward the apical end. The 
transverse striae are crossed by much finer vertical striae, of 
which 8 to 10 occur in a width of 1 mm. 
Hyolithes haconi is fairly common at one horizon near the top 
of the Plattin limestone, but most specimens do not show the 
low median elevation on the convex side of the shell and the fine 
