Potsdam of Wisconsin and Lake Superior. 229 
of all superficial ornaments. But three whorls have been seen; 
these are ‘66 inch in height, and the lower one is about “77 inch 
in diameter—the three being of nearly equal height. 
This fossil is quite unlike anything described from the Pots- 
dam sandstone; and there is nothing in the Calciferous sand- 
rock which approaches nearer than Holopea Proserpina Billings 
(Pamphlet, Jan. 1862, p. 28), with which this may be eongeneric. 
A DicettocerHatus PEPINENSIS, et : ce 
An imperfect cephalic shield shows a narrow border, with a 
decidedly thickene margin, which is broader than the furrow 
Yetween it and the front of the glabella. The glabella is prom- 
ment, with sub-parallel sides and an obtusely rounded anterior 
®xtremity. Opposite the middle of the prominent palpebral 
Am. Jour. Sct.—Szconp Series, Vou. XXXVI, No. 110,—Marcx, 1864. 
30 
