178 NEW YORK STATE MUSEUM 



with broadly expanded, regularly curving sides on which the median sinus is 

 low, with a flattened bottom and the fold correspondingly depressed; the 

 lateral slopes bear eight or nine ribs with three or two indistinct ones 

 besides near the cardinal angles; these ribs are regularly rounded and the 

 intervening grooves narrow and shallow. Distinguished from these are 

 individuals with deeper sinus having more angular slopes and making an 

 elevated and acute fold on the dorsal valve. The plications are few, six, 

 with traces of two or three others, are stout, with angular and deep grooves. 

 The internal casts of these shells are characteristic, the ribs appearing quite 

 angular and the muscle scar of the ventral valve very much more conspicuous 

 than in the other expression. Hall made no distinction among the New 

 York shells of this species but the variation indicated seems to be as well 

 defined in one province as in the other. Most of the specimens figured in 

 Palaeontology of New York, ut. cit. are of the latter type but the other 

 expression is well shown in figures le and if. 



In Museum memoir 3 [1901] I expressed the view that these differences 

 which had been in a measure indicated by Scupin' were of fugitive value 

 but the evidence derived from the Gaspe shells seems to indicate their 

 stability and persistence. Dr Scupin suggested that the term S p. 

 arrectus (==m u r c h i s o n i) be restricted to the forms with few and 

 strong fold and sinus, that is, our second type, and that the other was 

 identical with S p. antarcticus Morris & Sharpe, collected by Darwin 

 from the Falkland islands. This he proposed to call var, antarcticus 

 and to include with itS. chuquisaca Ulrich (Bolivia), S. orbignyi 

 Morris & Sharpe (Falkland islands) and S. capensis v. Buch (Cape 

 Colony). 



Localities. Common in many of the outcrops and along the shore at 

 Grande Greve and Lehuquet's ; rarer in the Perce Rock. 



Spirifer cyclopterus Hall 



Plate 32, figures 14-21 



Spir if er cy clop teru s Hall. Palaeontology of New York. 1859. 3:199, pi. 25, 



fig. ia-2 

 Spirifer cycloptera Billings. Palaeozoic Fossils, v. 2, pt i, 1874. p. 48, 



pi. 3A, fig. 4a-c 



The shells Billings referred to this species seem to show no characters 

 which would separate them from the Helderbergian form. The species is 

 not common on the Forillon. Billings reports Grande Greve and Indian 

 Cove. It also occurs at Perce. We have here figured Billings's original 

 specimens. 



' Zeitschr. der deutsch. geol. Gesellsch. 1899. 50:462. 



