468 WISCONSIN NATURAL HISTORY SURVEY 
slightly concave.” [Septa 5™™ apart at the chamber of habitation, and 3™™ 
apart 3°™ from the chamber. Siphuncle marginal.] 
This species resembles G. tumidum Hall of the Chemung shales of 
New York. 
It is possible that this is an old-age form of G. breviposticum. 
For discussion on this point see description of that species. 
Locality —Milwaukee Cement Quarry, Berthelet, Wis., especially abundant 
in the ‘‘hard layer;’’ ‘‘Whitefish Bay, near Milwaukee.” 
Fic. 14.—Exterior view of a remarkably well-preserved specimen of Gyroceras 
clarkei N. S., in which what appear to be traces of both transverse and longitudinal 
color markings are retained. The original is from the Public Museum, Milwaukee. 
Gomphoceras sp. 
(Fig. 8) 
Description.—An almost perfect specimen of a large Gomphoceras, differs 
from other Milwaukee cephalopods in that it is subfusiform and has a large 
chamber of habitation which contracts slightly toward the aperture. Septa 3 or 
4™™ apart near the chamber of habitation, but 9 to 1o™™ apart 6.5°™ from the 
chamber. Transverse section apparently elliptical. The greatest diameter 
appears to be at about the tenth septum. 
Locality.—Milwaukee Cement Quarry, Berthelet, Wis. 
