GASTROPODA. 253 



Actinopteria ? 

 Plate 67, figures 3, 4 



The Little Saline limestone affords a few fragmentary examples which are tenta- 

 tively referred to this genus. The pelecypods in general are represented by mere frag- 

 ments, and constitute a subordinate part of the fauna. 



Horizon — Lower beds. 



Figured specimens Nos. 27556, 27557, Walker Museum. 



Family Pectinidae 



Genus Aviculopecten M'Coy 



Aviculopecten sp. undet. 



Plate 67, figure 5 



A fragment of an Aviculopecten has been observed which is unsuitable for certain 

 determination. The surface is characterized by the presence of coarse distinct ribs, 

 with each intervening space divided by a lower less prominent rib, and the interspaces 

 marked by fine, indistinct striae. Concentric, undulating markings cancellate the ribs; 

 these are uniformly spaced at a distance of from 1.5 to 2 mm. apart. 



Horizon — Lower beds. 



Figured specimen No. 27558, Walker Museum. 



Class GASTROPODA 



Subclass Streptoneura 



Order Aspidobranchia 



Suborder Rhipidoglossa 

 Family Trochonematidae 

 Genus Strophostylus Hall 



Strophostylus allani sp. nov. 1 

 Plate 70, figures 9-15 



Description — Shell of medium size to large. The dimensions of the holotype which 

 is a large specimen are: Height 50 mm., width 40 mm. Shell consisting of three rapidly 

 expanding whorls, the inner one rising considerably above the outer; spire of medium 

 height; suture distinct; upper surface of volutions convex, sides obliquely rounded. 

 Aperture entirely sub-circular to broadly oval, and slanting obliquely backward below. 

 Character of inner lip cannot be determined from specimens observed. Surface marked 

 by coarse, irregular lines of growth, and on the outer volution these are crossed at right 

 angles by faintly defined striations. 



Remarks — -The species resembles Strophostylus transversus Hall, from the New 

 York and Maryland Oriskany, but is distinguished by the higher spire, and the more 

 distinctly irregular and imbricating lines of growth. 



Horizon — Lower beds. 



Holotype and Paratypes No. 27509, Walker Museum. 



'This species has been named after Professor J. A. Allen, head of the Department of 

 Geology, University of Alberta, Edmonton, Alberta, Canada. 



