28f) MR. J. W. KIRKBY ON SOME 



X. — On some Permian Fossils from Durham. By Mr. J. W. 



KiRKBY.* 



This communication comprises a notice of the occurrence of a 

 malacostracous Crustacean and of a new species of Chiton in tlie 

 Magnesian Limestone of Durham, together with remarks on 

 some other Permian fossils. 



1. PrvOsoroNiscus problematicus, Schlotheim, sp. PI. XII. 

 figs. 1-7. 

 Trilohites problematicus, Schlotheim, Petrefact. 1820, p. 41. 

 Palfeocrangon prohlematica, Schauroth, Zeitschr. deut. geol. 

 Gesell 1854, vi. }■). 560, pi. 2^, figs. 2, a-e. 



In the summer of 1853, I found two imperfect specimens of 

 one of the higher (malacostracan) Crustaceans in the limestone 

 at Humbleton Quarry. At the time I thought that the species 

 belonged to the Macrura ; but I now find this was an error. A 

 short notice of this interesting discovery appeared in the Address 

 of the President of the Tyneside Naturalists' Field Club, 

 March 15, 1854.t 



At that time I believed that none but the lower forms of 

 Crustaceans had been previously found in the Permian rocks. 

 I have since learned, however, that in Schiotheim's " Petre- 

 factenkunde," 1820, p. 41, mention is made of the discovery (in 

 the Zechstein-dolomite of Gliicksbrunn) of a peculiar fossil, 

 named by Schlotheim Trilohites prohlematicus, which is probably 

 the same species as mine. 



In 1854, Baron SchaurothJ authenticated Schiotheim's dis- 

 covery, and figured and described a specimen of this species as 

 belonging to one of the higher groups of Crustacea^ naming it 

 PalcEOcrangon prohlematicus. On comparing my specimens with 

 the figures given by Schauroth, I have a little hesitation in re- 

 garding them as belonging to the same species ; but as " Pal^eo- 

 crangon" does not express the affinities of the fossil animal, I 



* Communicated to the Geological Society- of London, and printed in their Quarterly 

 Journal, vol. xiii. p. 213. 

 t Traiisa'tions of the Tyneside Nat. Field Club, vol. ii. p. 333. 

 X Zeitschrift der deutsch. geolog. Gesell. vol. vi. p. 560, pi. 22, fig. 2. 



