235 



downward to fill the sinuosity in the front of the pedicle 

 valve; fine concentric surface striae and almost obsolete 

 faint radiating striae. 



Found in the upper layers of the Encrinal limestone, at 

 Section 5, in Eighteen Mile Creek ( rather common ). 



Genus TRIGERIA. Bayle. 



(1875: Explic. Carte Geol. de France, Atlas, PI. XIII. L893: Pal. N. Y., 



Vol. VIII., Ft. II., p. 272.) 



"Plicated centronellids with plano-convex valves. In the' 

 brachial valve the hinge plate is tripartite, the median 

 division being perforated by a visceral foramen. Brachidium 

 as in Centronella, though with a smaller anterior plate." 

 (Hall and Clarke. Hand-book Brach., Pt. II., p. 108.) 



Tkigeria (?) lepida. Hall. (Fig. 146A.) (Pal. N. Y., 

 Vol. IY.,p. 276, Pl.XLY.) 



Distinguishing Characters.— Small size; sub-equally con- 

 vex valves; much elevated beak of pedicle valve; elongate 



Fig. 146A. Trigeria lepida. Ventral view of a specimen, natural size. Dorsal, ven- 

 tral, and profile views of a specimen, enlarged, x 2. Dorsal view of an individual with 

 unusually strongly marked sinus (from Hall). 



oval opening, communicating with foramen above, and 

 flanked below by two convex deltidial plates; simple regular 

 surface plications, gradually enlarging towards the margins 

 of the valves; shallow sinus on brachial valve, formed by 

 depression of two or three central plications. 



Genus CRYPTOXELLA. Hael. 



[Ety. : Signifying a small cavity.] 



(1861: 14th Annual Rep't, N Y. State Cab. Nat, Hist., p. 102. 1893: Pal. 

 N. Y., Vol. VIII, Pt. II., p. 286.) 



Shell terebratuloid, with the valves of somewhat similar 

 convexity. Beak of pedicle valve erect or slightly incurved 



