214 



Si'iKiFEK MACRONOTUs. Hall. (Fig. 121.) (Pal. N. Y., 

 Vol. IV.. p. 231, PL XXXVIII. A. ) 



Distinguishing Chnraeters. — General resemblance to S. 

 audncuJus (of which it may be only a variety), differing 

 from that species mainly in the very high, flat, area, minnte 

 beak, comparatively shallow mesial sinns, which rapidly 



Fig 121. Spirifer inacronotus. Cardinal view of a larpe individual; lateral views of 

 two individuals, showing the character of the area (from Hall). 



widens towards the front, and the iinmber of plications, 

 which varies from fifty to seventy on each valve, of which 

 only three or four on each side of the fold and sinns reach 

 the beak: the delthyrium is more than twice as high as 

 wide, and the snrface of the shell exhibits lamellose, imbri- 

 cating growth lines. 



Fonnd in the Encrinal limestone, at Section 5 (common) ; 

 Stictopora and Demissa beds, at Section 5 (common) ; (me 

 and one-half to three feet below the Encrinal limestone, at 

 Section 6 (rare) ; shale below the Trilobite beds, in Avery's 

 Ravine (rare). 



Spikifek ASPER. Hall. (Fig. 122.) (Geol. Snrv. of Iowa, 

 1858, Vol. I., Pt. II., p. r,()8, PL IV.) 



Distinguisliing Clmracters. — Small size; snb-pyramidal 

 outline; high, flat cardinal area of pedicle valve; narrow 

 and high delthyrinm ; broad, comparatively shallow sinus, 



