218 



pf?0 



Fig. 119A. Spirifer audaculiis, var. eatoni. Dorsal, profile, cardinal, and front views 

 of a characteristic specimen (from HallV 



Spirifer ANGUSTUH. Hall. (Fig. 120.) (Pal. N. Y., Vol. 

 IV., p. 230, PL XXX VIII. A.) 



Distinguishing Cliaracters. — Depressed pyramidal outline; 

 great lateral extension; pronounced inequality of valves; 

 pedicle valve forming nearly the entire thickness of the shell, 



► 



Fig. 120. Spirifer angustus. Dorsal, profile, ventral, and cardinal views of a 'large 

 specimen, with extended cardinal extremities and a high cardinal area (from Hall). 



with an area equaling in height the length of the shell; 

 delthyrium about twice as high as wide, grooved on the 

 sides; brachial valve flat, with a narrow area and low 

 mesial fold ; surface plications fine, simple and rounded, 

 from forty-eight to flfty-six on each valve. 



Found in the Demissa bed, at Section 5 (rare). 



