222 ROYAL SOCIETY OF CANADA 



of the species. Specimems from the Oriskany of Cumberland, Md., also 

 show the same characteristics. The specimens figured by Dr. Clarke 

 from the Grande Grève limestone (Plate 33) show about the same stage 

 of evolution tho' some specimens in that fauna are further advanced and 

 one specimen is identified with the extreme form Spirifer unicus. Hall. 



16. Spirifer montrealensis, sp. nov. Plates I and II. 



In the list of species from the brecciated limestones of St. Helen's 

 Island, Donald ^ mentioned a species as " Spirifer allied to S. arenosus 

 {Conrad)." Schuchert re-examined the material and reported that the 

 reference " relates to a Spirifer apparently near S. granulosus, Conrad." 2 



In a later discussion of the fauna Schuchert made the following 

 comment on this form : 



"Spirifer, cf. granulosus {Conrad). Associated vith S. Macra, 

 there is a more rotund species, ivith high, slightly incurved ventral area, 

 angular sinus, and prominent dental plates. These are characters asso- 

 ciated loith S. granulosus." ^ 



Specimens received from the original locality, from Dr. F. D. Adams, 

 have been examined and are found to present distinct specific characters, 

 which form the basis of the following description, the tj^pe being num- 

 bered Ko. 5380.1 & 2. (See PI. 1, Fig. 8 ajud 2) 934 and 935, U. S. 

 Geol. Survey. Specimens 934 '(fig. 8) is the exterior of a nearly com- 

 plete specimen of the pedicle valve attached to a distorted and incom- 

 plete valve. No. 935 (fig. 2) is a nearly complete brachial valve; both 

 are exfoliated. Both specimens present considerable resemblance to a 

 medium sized specimen of Sp. granulosus. Tiie specimen (fig. 8) shows 

 the following dimensions : greatest width at hinge line 54 nvn., greatest 

 width just under the mucronate points of the wing 50.6 mm., distance 

 from end of beak to front in straight line 35.7 mm. The plications are, 

 however, more numerous and finer than on Sp. granulosus. At a distance 

 of 15 mm. from the point of the beak about 20 plications are visible each 

 side the medium sulcus; on^ie brachial valve 19 to 20 can be counted on 

 each side the fold. The beak of the pedicle valve is rounded and arched 

 over the area, the area is about 8 mm. high under the beak. Specimens 

 of S p. granulosus of approximately the same size, show only 17 plications 

 each side, and those near the middle are decidedly larger than in this 

 species. 



1 Donald, J. T., Canadian Naturalist, N.S., IX. ISSl, p. — . 



2 Schuchert, C. Bull. Soc. Geol. Amer., Vol. II, 1000, p. 332. 

 •i Am. Geologist. XXVII. 1901, p. 252. 



