Vol. 59.] KEISLEY LIMESTONE-PEBBLES IN PEEL SERIES. 307 



22. Note on the Occurrence of Keisley Limestone-Pebbles in the 

 Eel Sandstone-Rocks of Peel (Isle of Man). By E. Leonard 

 Gill, Esq., B.Sc, Curator of the Natural History Museum 

 at Newcastle-upon-Tyne. (Communicated by Prof. W. Boyd 

 Dawkins, M.A., D.Sc, E.R.S., E.G.S. Read April 8th, 1903.) 



In his receut paper on ' The Red Sandstone-Rocks of Peel,' l Prof. 

 Boyd Dawkins mentions a rock which occurs in a derived form in 

 one of the conglomerates of the Peel Series, and has been identified 

 with the Keisley Limestone. When Prof. Boyd Dawkins was pre- 

 paring the paper quoted above, he entrusted to me the examination 

 of the pebbles of the rock in question ; and as the resulting identi- 

 fication possesses an interest apart from the main issues of his own 

 work, he has kindly offered me the opportunity of giving a separate 

 account of it. The following notes, therefore, contain a brief 

 description of the rock and its fossil contents, with the grounds for 

 believing it to be identical with the Keisley Limestone. 



The pebbles which formed the material for the investigation were 

 collected by Prof. Boyd Dawkins from the conglomerates forming 

 the coast-line at Whitestrand, near Peel (Isle of Man). 2 They are 

 composed of a coarsely-crystalline limestone, greyish-white in 

 ground-colour, and as a rule thickly mottled with pink : agreeing, 

 in fact, very closely with those beds of the Keisley Limestone which 

 Mr. E. R. Cowper Reed, M.A., E.G.S. , speaking of their lithology 

 in his exhaustive paper on that group, 3 describes as Type 3. The 

 amount of this limestone available for examination was not great ; 

 and at first, as no fossils more distinctive than ostracods and some 

 small and indefinite brachiopods had been met with, it was thought, 

 on the strength of other fragments with which it was associated in 

 the conglomerate, that this rock was derived from the Carboniferous 

 Limestone. On breaking up the pebbles, however, the discovery of 

 several heads of Illcenus Bowmani and shells of Plectambonites 

 quinquecostata proved it to be of Ordovician, and probably of Bala, 

 age. My attention was then directed by Mr. P. F. Kendall, F.G.S., 

 to Mr. Cowper Reed's papers on ' The Eauna of the Keisley Lime- 

 stone,' 4 and a striking correspondence in several particulars was at 

 once evident. The three most characteristic fossils in the pebbles 

 collected by Prof. Boyd Dawkins were 



Plectambonites quinquecostata ; 

 A small Euompkalus-like gasteropod ; and 

 ' Illcenus Bowmani. 



Of these, the Plectambonites is found commonly enough in the Keisley 

 Limestone ; the Eaomphalus-like shell appeared to agree exactly 



1 Quart. Journ. Geol. Soc. vol. lviii (1902) p. 642. 



2 Ibid. p. 641, Table. 3 Ibid. vol. liii (1897) p. 100. 

 4 Ibid. vol. lii (1896) p. 407, & vol. liii (1897) p. 67. 



Q. J. G. S. No. 235. z 



