■248 PROCEEDINGS OF THE ACADEMY OF [1888. 



centimetres ; dorso-ventral diameter of outer chamber nearly six 

 centimetres. It has been found at various exposures of Hamiltonian 

 limestone in Johnson and the contiguous counties. It appears to 

 be closely related to certain species from the Niagarian of the west- 

 ern states. 



Explanation of Plate XII. 



Fig. 1. Macrocheilus humilis n. s page 



Enlarged about 5 diameters. 

 Fig. 2. Pleurotomaria modesta n. s 



2a. View from above, X 2. 



2b. Profile, X 2. 

 Fig. 3. Chonetes Icevis n. s 



3a. An average sized specimen, X 2. 



3b. Longitudinal section, X 2. 

 Fig. 4. Conocardium altum n. s 



4a. Lateral view. 



4b. Dorsal outline. 

 Fig. 5. Cyrtoceras ojnmum n. s « 



Reduced to f natural size. 



• • 



