602 Karl A. Grönwall. 



Etheridge's interpretations of their relationship with European 

 species". 



Whitfield's revision of Etheridge's determinations leads him 

 to the result that in the greater number of the cases, where he 

 considers his specimens are in agreement with a name given by 

 Etheridge, he has been able to identify the specimen in question 

 with an Upper Carboniferous species, or as showing a certain relat- 

 ionship with one. As regards age the Coal Measures of North 

 America are, of course, Upper Carboniferous. 



Of the little fauna at his disposal he gives illustrations of a 

 couple of species, and some of these plates afford us an opportunity 

 of drawing comparisons with forms from the Carboniferous fauna 

 of North-east Greenland and of Spitzbergen. A species of Productus 

 is referred to Pr. semireticulatus, with the following reservation (1. с 

 p. 55) : "If it is to be referred to it at all I would suggest it to be 

 coupled with the term arctica as Productus semireticulatus arctica". 

 This form is pictured on PI. 2 as Figs. 8, 9, 10, and a careful exam- 

 ination of these figures places it beyond all doubt that it is the same 

 as the one from Spitzbergen that Wiman determined as Prod, infla- 

 tus M'Chesn., and which is also found in the Carboniferous deposits 

 of North-east Greenland, In the group of fossils reproduced in PI. 

 1, all the Productus shells, with the exception of the uppermost 

 (marked 1), belong lo Pr. infiatus M'Chesn., viz., 4 more or less complete 

 ventral valves, and a fragment of a dorsal valve, at the bottom to 

 the left of the plate. 



The commonest Productus species in the Carboniferous deposits, 

 both of Spitzbergen and of North-east Greenland, is Pr. timanicus 

 Stuck., and this species is probably also represented among the 

 fossils from Cape Sheridan, for, of the specimens figured by Whit- 

 field, I am inclined to refer 4 to this species. 



Of these four, 2 are figures of older individuals that have attained 

 larger dimensions than any of my specimens, and are little inferior 

 in size to those given by Wiman, with which I wish to compare 

 Whitfield's specimens, viz., PI. 1, with the specimen marked 1 in 

 the upper part of the photograph, and PI. 2, Fig. 11. The former 

 shows a ventral valve, which I should like to compare proximately 

 with Wiman's pi. 17, Fig. 20, while Fig. 11, PI. 2 I should like to 

 compare (in spite of the fact that Whitfield's figure shows few 

 details) with Wiman's PI. 17, Fig. 21; it (Whitfield's) is a dorsal 

 valve seen posteriorly, and the figure shows both the evident 

 mesial elevation corresponding to Ihe sinus, and the flattening of 

 Ihe valve towards the corners, indicating the wings, and the spines 

 at the hinge-line. 



