204 



» 



^^Jtt^ 



,^ 



Fig. no. Chonetes corovatus Profile of the pediele vjihe, shown in full view helow it ; 

 ventral and profile views of another specimen; two niteriors of brachial valves, siiowing 

 differences in cardinal process, strength of muscular impressions, etc. (from HalO. 



and G: Plenrodictviini beds and shale above, in Avery's 

 Creek. 



Genus PRODUCTELLA. Hall. 



[Ety. : Diminutive of Productus.] 



(1867: Pal. K Y., A'ol. IV., p. 153. 1892: Pal. N. Y., 

 Vol. VIII., Pt. I., p. 328.) 



Shells small ; concavo-convex, the pedicle valve strongly 

 convex, and produced anteriorly. The beak of the pedicle 

 valve is overarching', and the hinge line straight, with a nar- 

 row cardinal area, a deltidinm and small teeth. Rrachifd 

 valve small, concave operculiform, with a straight hinge 

 line, dental sockets, and crural plates. Sui-face marked by 

 radiating ridges, which bear spines at intervals. 



Productella XAVicELLA. Hall. (Fig. 111.) (Pal.N.Y.. 

 Vol. IV., p. 156, PL XXHI.) 



Distinguishing CliarHcters. — Small size; great length. 



which exceeds the 

 A^idth ; hinge line less 

 than width of shell : 

 pedicle valve verj^gib- 



FiG. 111. Productella navicella. Dorsal, ventral and UOUS, Wltll the beak 

 profile views of an elongated specimen of the variety ,..,,,^1, ;,, ,,,,,.rA 1 



occurringin the Encrinaf limestone (from Hall). ^ ^l" \ mUCll lllClUVed, 



