340 Kirkhy and Young — On Fossil Chitons. 



n. — Notes on some Eemains of Chiton and Ghitonellus from 

 THE Carbonifekous Strata OP Yorkshire and the West of 

 Scotland. 



By Messes. James W. Kirkby and John Young. 

 (PLATE XVI.) 



SINCE the occurrence of Chitons, in the Mountain Limestone of 

 Settle, was noticed by one of us, in 1862,^ other remains have 

 been found in the same rock, as well as in the Carboniferous Lime- 

 stone and shales of Scotland. The former were discovered, as before, 

 by Mr. J. H. Burrow, of Settle, who has kindly placed them in our 

 hands for description. 



Both suites of remains are, as is usual with fossils belonging to 

 this group of mollusca, in the state of isolated plates. Those from 

 Yorkshire are from the Lower Scar Limestone, where they are found 

 associated with gTeat numbers of other fossils, such as Orthoeeras Gold- 

 fussianum, De Kon. ; Goniatites striatus, Phillips ; Spirifera cuspidata, 

 Ehynchonella angulata, etc., etc. Those from the West of Scotland 

 are from the calcareous shales of the Lower and Upper Limestone 

 series of Oraigenglen, Campsie ; Williamwood, near Cathcart, Een- 

 frewshire ; Braidwood, near Carluke ; and Eobroystone, N.E. of Glas- 

 gow ; and they, like the Yorkshire specimens, occur associated with 

 many other marine fossils. 



The Scotch specimens do not appear to have been much worn or 

 corroded before they were imbedded in the rock materials. The 

 Yorkshire plates, on the contrary, are nearly all more or less injured 

 in respect to surface. They are likewise thick-shelled compared 

 with the Scotch species, and seem to have been adapted, as well as 

 subjected, to the wear and tear of a rock-bound coast. 



Description of Specimens from Yorkshire : — 



1. Chiton Burrowianus, Kirkby, 1862. [Quart. Journ. Geol. Soc. 

 vol. xviii. p. 234, figs. 1 and 2.] Plate XVI. Figs. 14 and 15. 



This species was described from two plates, a posterior and an intermediate one. 

 Other two have been found by Mr. Burrow, which are likewise posterior and inter- 

 mediate. The last found posterior is larger than the first, being an inch in width and 

 five-eighths in length. It is much worn and does not show any additional feature. 

 The intermediate plate has apparently belonged to a smaller individual and is not 

 quite perfect. 



2. Chiton coloratus, Kirkby, 1862. [Quart. Journ. Geol. Soc. vol. 

 xviii. p. 234, figs. 3, 4, 5, 6.] Plate XVI. Figs. 8a, 86. 



Several imperfectly preserved posterior plates occur. Also an anterior plate, 

 which is very thick-shelled, and which has a worn surface that retains traces of gra- 

 nulation. The anterior margin forms rather more than a semi-circle ; the posterior 

 is concave on each side of the apex, and projects backwards to join the anterior 

 margin. Length three-eighths of an inch ; width half an inch ; height three-sixteenths 

 of an inch. 



3. Chiton Loftusianus, King, 1848. [Catalogue of Org. Eem. Perm. 

 Foss. p. 12.] Plate XVI. Fig. 17. 



In a former paper,^ by one of us, an intermediate plate of a Chiton is figured that 

 greatly resembles those of C. Loftusianus, King, of the Magnesian Limestone. Its 

 resemblance to that species was pointed out, though it was not identified with it. 

 1 Quart. Journ. Geol. Soc. vol. xviii. p. 233. ^ n^ij. p. 236. 



