282 

 GENii^ LEIORHYXCHUS. Hall. 



[Etv. : Lei'os, smooth; rliyitchos, beak.] 



(18G0: lath Ann. Rep't N. Y. State Cab. Nat. Hist., p. To. 

 1893: Pal. X. Y., Vol. VIII., Pt. II., p. 193.) 



Rhynelioiielloid shells, with the plications on the median 

 fold and sinns hiuhly developed, but those on the lateral 

 slopes usually slightly developed. Other external features 

 as in Camarotfpchia. 



Leiorhyn'Chus MrLTR'osTus. Hall. (Fig. 142.) (Pal. 

 N. Y., Vol. lY.. p. 858, PL LYI. ) 



Distinguishing Clmracters. — Ovate outline; length and 

 greatest width nearly equal (except in compressed speci- 



FiG. 142. Leiorhynchus muUicostns. Cardinal view of a gibbous specimen: two l)rach- 

 ial valves of different ages; three pedicle valves, one much distoi-ted (from Hall). 



mens) : three to seven rounded plicaticms in the sinus and on 

 the fold, all bifurcating; obscurely bifurcating lateral plica- 

 tions, which become obsolete near the beak ; concentric 

 strifv. This species is considered identical with L. Jaur;i 

 (Billings). 



Found in the upjter and lower Moscow shales, at Sections 

 1 to 8, and on the Lake Shore (especially abundant in the 

 Schizobolus beds); Lower shales, five feet below, and from 

 fourteen feet below the Encrinal limestone do^vn, at Sec- 

 tions 7 and 8, and on the Lake Shore (often abundant). 



