EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA I 83 



that the convexity of this valve is largely a condition of immaturity and the 

 Ambocoelia aspect becomes hightened with increase of age. Neither of 

 these shells gives evidence of fimbriation. 



Locality. Shore outcrops at Grande Greve. 



Spirifer sp. ? 



Plate 32, figures 24, 25 



We find two dorsal valves characterized by their low median fold, 

 depressed lateral slopes and smooth nonplicate surface. One of these 

 apparently had a fine lineate surface ornament. The valves pertain either 

 to a Spirifer or Cyrtina of unusual type. 



Localities. Grande Greve and Indian Cove. 



Cyrtina rostrata Hall 



Plate 31, figures 25-28 



Cyrtia rostrata Hall. Palaeontology of New York. 1859. 3: 429, pi. 96, fig. 



1-6; pi. 98, fig. 8 

 Cyrtina affinis Billings. Palaeozoic Fossils. 1874. v. i, pt 2, p. 49, pi. 3A. 



fig. 6, a, b 

 Cyrtina rostrata Hall & Clarke. Palaeontology of New York. 1894. v. 8, pt 



2. pi. 25, fig. 1-8; pi. 28, fig. 6 

 Cyrtina varia Clarke. N. Y. State Mus. Mem. 3. 1900. p. 49, pi. 6, fig. 15-22 



In species as variable as those of Cyrtina there is little to distinguish 

 the representatives of the genus which have been described from the 

 Oriskany fauna. Hall's figures ofC. rostrata were somewhat based on 

 old and thickened shells and this fact led Clarke to introduce the term C. 

 varia for shells from Becraft mountain which presented some variation in 

 size and incurvature and lacked the aspect of typical examples of C. 

 rostrata. This same expression is maintained by the shells abundant in 

 the Glenerie Oriskany, and between the usual habit of the latter, which are 

 as a rule larger than those obtained in Columbia county, and that of C. 

 affinis there is no distinction in form, plication or mode of variation. As 

 to the identity of these forms with Hall's C. rostrata, which was described 

 from the Oriskany of both Albany county and Cumberland, Md. and has 

 been identified by Schuchert in the beds at Cayuga, Ontario, there is no 

 reason for doubt. 



Localities. Among the less common forms in the upper limestones at 

 Grande Greve ; also at Perce. 



Leptaena rhomboidalis (Wilckens) 



Plate 34, figures 1-3 

 For synonymy see Palaeontology of New York, 1892, v. 8, pt i, p. 276. 



Specimens of this ubiquitous and long lived shell are not specially 

 common in this formation, the individuals usually being of the habit 



