208 



Found in the Moscow shales, at Sections 2, •">. 4 (rare); 

 Enerinal limestone, ;it Section 5 (rare); Hamilton shales, at 

 Sections 5 to 8, and on the Lake Shore (everywhere abun- 

 <iani i: Strophalosia bed and Transition shales, on the Lake 

 Shore i not uncommon ) : Marcellus shales, on the Lake* Shore 

 i rare i. 



Measurements. — A very much extended individual gave: 

 width, loo mm.; height, 15 mm.; average width is less. 



Spirifek tullius. Hall. (Fig. 115.) (Pal. N. Y., Vol. 

 IV., p. 218, PI. XXXV.) ■ 



Distinguishing Characters. — Small size (especially so in 

 this region); gibbous character ; sub-elliptical outline; well- 

 defined sinus, which extends quite up to the beak; strongly 



v>' 





Fig. 115. Spirifer tullius. Ventral and cardinal views of pedicle valve and brachial 

 valv of the normal form, as it occurs in the center of the State ; the Eighteen Mile Creek 

 specimens are much smaller (from Hall;. 



marked fold, which is wide at the bottom and narrow at 

 top; comparatively high cardinal area of pedicle valve: low, 

 round and rather flattened surface plications; and fine, 

 uniform radiating stria;, which are especially well visible be- 

 tween the plications, on the fold and in the sinus; faint 

 concentric striae also occur. 



Found in the Styliolina band, at Section 1 ; upper Moscow 

 shales, between one and one-half and three feet below the 

 Styliolina limestone, at Sections 2, ■'>, 4 (common). 



Measurements.— Average specimen in this region: width. 

 8 niiii.: heighl . ~> mm. 



Spibifeb (Delthybis) sculptilis. (Hall.) (Fig. 116.) 

 (Pal. \. V.. Vol. IV.. p. 221, PI. XXXV.) 



Distinguishing Characters.— Medium size; gibbous char- 

 acter; serai-elliptical to sub-triangular outline; extended 

 hinge line; sub-angular sinus, and strongly elevated fold. 



