THE KIMMSWICK AND PLATTIN LIMESTONES 209 
rise from the lateral margins as far as the slightly raised lines on 
each side of the median groove, forming an angle of about 75 
degrees with these raised lines. Between these lines the trans- 
verse lines curve so as to cross the median groove without any 
interruption or abrupt change of direction. 
The number of transverse striae varies from 6 to 9 in a length 
of 1 mm. near the smaller end of the specimen and also farther 
up, at midlength. At the larger end, where gerontic conditions 
appear to have set in, the number of these transverse striae equals 
11 to 12 in 1 mm. The transverse striae are very narrow, and 
their crests are lined with minute granules, numbering from 11 
to 17 in a distance of 1 mm. on various parts of the shell. The 
granules are arranged also in vertical rows. The linear areas 
between the transverse striae are depressed into broad and rather 
shallow grooves. Along that margin of the grooves which is 
nearer the apical end of the shell, very low granules appear, but 
th se granules alternate in position with those on the transverse 
striae and are visible only under a lens. 
The transverse striae cross the pair of slightly raised vertical 
lines along the median part of the face, as though these lines did 
not exist. The raised lines appear to be due to features not on 
the exterior but on ‘the interior of the shell. Along the raised 
lines the interior of the shell appears to be thickened. In a 
fossil state this thickened part tends to be preserved better 
than the adjacent parts. Moreover, during fossilization it 
tends to be lifted slightly above the adjacent parts. The 
median groove appears to locate a line of weakness in the shell. 
In cross-sections the raised lines are seen to be due to the 
presence of a pair of very short longitudinal septa on the 
median part of the inner side of each face of the shell. 
Found at the top of the Plattin limestone at Conn’s Ford, four 
miles northwest of New London, in Balls County. Named in 
honor of A. W. Heyman, in memory of many days spent on 
geological trips in Ohio and Missouri. 
Conularia heymani differs from Conularia granulata Hall 
(Pal. New York, 1, 1847, p. 223, pi. 59, figs. 5 a, b), from the 
Trenton at Middleville, New York, in the absence of distinct 
vertical striae connecting the vertical rows of granules. 
