EARLY DEVONIC HISTORY OF NEW YORK AXD EASTERN NORTH AMERICA 1 47 



Some of the representatives of this species in the Perce Rock attain 

 notable and occasionally extraordinary size. While the New York shells 

 have a length from apex to stoma averaging 45 mm, the former are not 

 infrequently 70 mm long, and a single fragment indicates a length of more 

 than 10 cm. The exterior of the shell as indicated by a Grande Greve 

 example is covered with fine concentric lines caught back at intervals along 

 revolving lines corresponding to the folds of the interior. The species is 

 of more slender form than P. d e n t a t u m Hall of the Onondaga limestone. 



Localities. Rather common at Perce Rock. Rare in the chert bearing 

 beds at Grande Gr^ve. 



Platyceras guesnini nov. 



Plate 14, figures 17-19 



Shell of medium size, suberect, subsymmetrically coiled ; apex deeply 

 coiled in horizontal plane, rapid expansion beginning at i^ volutions, body 

 whorl irregularly expanded, subcircular in cross section, direct and unat- 

 tached for one half its length. Surface without revolving furrows and 

 ridges, and marked with subequidistant concentric undulating fringes gradu- 

 ally becoming obsolete near the aperture ; also traversed longitudinally by 

 very fine revolving lines. 



Locality. Perce Rock. 



Species name. Hilarion Guesnin, Recollet Missioner at Perce about 

 1670. 



Platyceras lejeunii nov. 



Plate 14, figure 12 



Shell of medium size with relatively small coil and rapidly expanding 

 suberect body whorl. Surface with subspiral or somewhat twisted longi- 

 tudinal ridges crossing and festooning irregular concentric growth lines. 

 The surface is covered with very long and slender spines which are curved 

 or arched backward. The shell is more slender than other echinate species 

 and the spines relatively longer and more arched. 



Locality. In the upper beds at Grande Greve. 



Species name. Lejeune, the first of the Jesuits to arrive in Gaspe 

 after the recovery of Canada from the English in 1632. 



Platyceras (Orthonychia) belli nov. 



Plate 14, figures 20, 21 



Shell erect, minutely arched and incurved at the apex, expanding very 

 gradually but equally for nearly one half its length and thence more 

 abruptly, the cross section of the whorls being essentially circular and the 

 stomal margin undulated. Surface crossed transversely by rugose concen- 

 tric growth lines, their undulations corresponding to low grooves and folds 

 of the shell. Length of a full-sized specimen 50 mm ; stomal width 33. mm. 



