56 



THE GEOLOGIST. 



discovered at Bowertrapping, in Scotland ; and which I was happy, 

 to recognise among some duplicates kindly presented to me by Mr. 

 Young. Prod. GriffitMamis de Koninck has been recorded by Mr. 

 Morris and others as a British species ; but no examples referable to 

 that shell have come under my observation. We need not prolong 

 our observations with reference to the other well-known species of 

 this important genus, but pass at once to Chonetes, for its species 

 appear still involved under considerable confusion, and will require 

 much further investigation under favourable circumstances before 

 they can be properly or satisfactorily arranged. The difficulty is 

 principally caused by a number of badly defined so-termed species, 

 fabricated in Ireland and America on insufficient material. 



The only British species which I have been able to recognise with 

 any degree of certainty are G. comoides, G. jjafilionacea, G. Buchiana, 

 G. Hardrensis, and perhaps G. Dcdmanio/na ; but I am still uncertain 

 with reference to this last, (although we possess examples identical 

 with those of Belgium,) on account of the great resemblance certain 

 specimens bear to others of G. papilionacea. C. Buchiana appears 

 to be a well marked species, on account of its fewer or stronger ribs ; 

 but these also vary to a considerable extent. It is quite evident that 

 the shell figured as Lept. crassistria, by Prof. M'Coy, in the " British 

 Pal. Fossils" is a synonym of C. Buchiana; but I am still under some 

 uncertainty whether the typical form of G. crassistria, published in 

 the " Synopsis," be really the same. Anyhow, on accouut of its 

 fewer and simpler ribs, it will be preferable to provisionally locate 

 both it and G. tuberculoma under G. Buchiana as uncertain varieties. 

 The next difficulty is in the determination of what are the synonyms 

 of the good species for which we have retained the designation of 

 C. Hardrensis, and of which C. sub-minima and G. gibberula in M'Coy 

 are evidently synomyms ; but I would not venture to speak with so 

 much confidence with reference to G. volva, G. sulcata, C. perlata, and 

 G. serrata, M'Coy, all established on imperfect Irish specimens ; 

 but it is at the same time highly probable that if not all, the greater 

 number are simple variations in shape of a single species. All we 

 know of C. sulcata consists of a single ventral valve. C. (L&pt.) serrata 

 is fabricated from not even half ot a similar valve ! G. volva bears 

 much resemblance to C. Hardrensis ; while G. perlata is perhaps also 

 a small variety of the same ? C.polita, M'Coy, although described as 

 smooth ? looks very like many examples of C. Hardrensis or G. volva ? 

 in which the ribs are somewhat obliterated. It would therefore 

 be impossible with the scanty material at my command ; and in the 

 present state of our information to determine which of these Irish 

 forms are species or synonyms ; and it would therefore be very desir- 

 able that Irish geologists or collectors should carefully assemble 

 numerous specimens of Chonetes from the localities where the 

 so-termed species were mentioned to occur. The C. Laguessiina 

 stated to occur at Derwick in England, and Rahoran in Ireland, is 

 probably also nothing more than a variation of Hardrensis ? Having 

 done all that was within my power to clear up these difficulties, 



