208 
AUG. F. FOERSTE 
smaller than mature specimens of Maclurina manitohensis, the 
umbilicus apparently enlarged at the same rate and the keel 
surrounding this umbilicus rises at about the same angle. In 
Maclurina cuneata the keel rises much more rapidly, and the 
umbilicus is much narrower. 
24. Maclurites sp. 
A single specimen, 50 mm. wide, from the Hormotoma major 
zone on Sanders branch, is referred to Maclurites on account of 
the relatively wide umbilicus. The specimen may be regarded 
as a depressed form of Maclurites big shy i Hall, a Platteville 
species found in Wisconsin and Minnesota, the shell being more 
depressed even than figure 7 on plate 75 of the Paleontology of 
Minnesota, III, part 2, 1897; moreover, the peripheral angle is 
more acute and the umbilicus exposes fewer volutions. Com- 
pared with Maclurites depressus Ulrich, from the Platteville of 
Minnesota, the width of the umbilicus is similar, and the per- 
ipheral angle is only moderately greater, but there is no tendency 
toward concavity on the flattened side of the volutions. Com- 
pared with Maclurites crassa, Ulrich and Scofield, and its variety 
macra, the umbilicus is much smaller, and the peripheral angle 
is more acutely rounded. 
25. Conularia heymani sp. nov. 
Plate XXI, fig. 12, plate XXII, fig. 12 
Only one of the four faces of the shell is exposed and even of 
this face the lateral margins are not distinctly defined. As far 
as may be determined from the part exposed, the lateral margins 
of the one face here described diverge at an angle of about 15 
degrees. The median line of the face is occupied by a narrow 
groove, on each side of which is a slightly raised line, light brown 
in color, ^t the smaller end of the specimen the raised lines are 
about 0.8 mm. apart; 20 mm. farther up they are about 1.25 
mm. apart. Beyond this point they can not be measured accu- 
rately. The face is crossed transversely by very fine striae which 
