213 



■: fr**^ 



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

 of a characteristic specimen (from Halll. 



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

 IV., p. 230, PL XXXVIII.A.) 



Distinguishing Characters. — 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 fifty-six on each valve. 



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



