﻿PRODUCTION. 



95 



published under the denomination of C. liar dr ends cannot be doubted, and the only 

 question upon which some uncertainty might prevail is whether C. Hardrensis might 

 not be a synonym of C. sordida, or even of C. snrcinufata, of the Silurian period. 

 Phillips, in his work on the Pal. Foss. of Devon, &c, describes C. sordida and C. 

 Hardrensis as distinct species. De Koninck places both these so-termed species under 

 C. sarcinulata, and Dr. Sandberger follows in the same track. In their ' Memoir on 

 the Fossils of the Older Deposits of the Rhenish Provinces,' published in vol. vi, 

 of the Transactions of the Geological Society, Messrs. d'Archiac and de Verneuil have 

 retained C. sordida and C. Hardrensis as distinct species, and Prof. M'Coy, at p. 386 

 of his ' British Palaeozoic Fossils,' describes C. sordida, without announcing any synonyms, 

 under the designation of Leptana [Strop horn end) sordida (Sow.), and concludes by stating 

 that he suspects the Linton shell referred by Prof. Phillips (Pal. Foss.) to the Silurian 

 0. cumpressa to belong to the present species. I have already had occasion to observe 

 that this view may be partly correct, for some of Phillips's figures of 0. compressa do, in 

 all probability, belong to C. sordida or Hardrensis, and one or two of them to Strep, 

 crenistra. One of the original specimens of Sowerby's Leptcena sordida may be seen in 

 the Museum of the Geological Society, and without doubt must be referred to the genus 

 Chonetes, and not to Leptcena; but they are, as remarked by Sowerby, very imperfect speci- 

 mens, and their exterior badly preserved, so that from the typical examples no very satisfactory 

 description could be given. 1 I prefer, therefore, to retain the name Hardrensis in pre- 

 ference to that of sordida (supposing the two names to be synonymous), because Phillips's 

 description and figures leave no uncertainty as to the species he intended to describe. 

 Leptcena convoluta, Phillips, appears to be nothing more than a somewhat deformed speci- 

 men of C. Hardrensis. 



C. Hardrensis is exceedingly common in the Upper Devonian Grits and Shales of 

 North Devon. At Marwood and Braunton it is very abundant, but the specimens are 

 usually small. It occurs also in several localities in the neighbourhood of Barnstaple ; at 

 Linton, and in other localities. Mr. Pengelly has found the shell in dark grey slate at 

 Black Hall, near Totness. It has now been obtained from dark shales in the Eifel, in 

 Nassau, and several other localities. 



1 Sowerby describes his Leptcena sordida with the following words : " Transversely elongated, rather 

 convex, irregularly striated, hispid ? Muscular impressions occupying half the internal area ; hinge-line 

 nearly as long as the width of the shell, its angles rounded. Width variable, sometimes nearly double 

 the length (Loc. Linton)." We have also in our PI. XIX reproduced the original figures. 



