﻿Vol. 6 1.] IN" THE NORTH-STAFFORDSHIRE COAL-MEASURES. 527 



(i) Northumberland and Durham Coalfield. 



1860. Kirkby, J. W. Quart. Journ. Geol. Soc. vol. xvi, pp. 412-14. 



1861. Davidson, J. Pal. Soc. : 'Monogr. Brit. Foss. Brachiopoda ' vol. ii, p. 209. 

 1873. Hull, E. ' The Coalfields of Great Britain ' 3rd ed. p. 257. 



1886. Leboue, G. A. ' Outlines of the Geology of Northumberland & Durham ' 



2nd ed. pp. 43, 54, 68, & 109. 

 1888. Kibkby, J. W. Quart. Journ. Geol. Soc. vol. xliv, p. 752. 

 1897. Leboue, G. A. Proc. Univ. of Durham Phil. Soc. vol. i, p. 69. 



X. Notes on the Paleontology. By Dr. Wheelton Hind. 



Introduction. 



It has been known for some time that thin bands containing marine 

 shells occur in several coalfields, and from time to time figures and 

 descriptions have been published. Among the earliest of these 

 publications were Sowerby's descriptions and figures of the marine 

 mollusca from the Pennystone Ironstone of Coalbrookdale, in Prest- 

 wich's memoir. 1 Perhaps the other most important publication is 

 that by Mr. George Wild, in which a large number of marine 

 mollusca were figured. 2 



So well known was the occurrence of marine fossils, as distinct 

 from the bands of Carbonicola, Anthracomya, and Naiadites, that 

 Prof. Hull, in his paper on ' The Upper Limit of the Essentially- 

 Marine Beds of the Carboniferous Group of the British Isles', 3 

 included the Gannister Series or Lower Coal-Measures with the 

 Millstone Grits and the series of shales and black limestones below 

 them, which he erroneously correlated with the Yoredale Series of 

 Wensleydale. 



This classification is obviously unsound ; (1) because the 

 Gannister Series is not wholly marine in origin, for it contains 

 beds in which the marine fauna is absent ; and (2) a marine fauna 

 is not limited to the Gannister Series, but recurs at several 

 horizons in the middle portion of the Coal-Measures, which are 

 therefore not ' essentially freshwater or estuarine beds.' Indeed, 

 there is an unbroken succession from the base of the Pendleside 

 Series to the top of the Coal-Measures, at times marine, at times 

 estuarine, or of freshwater origin. This thick series contains two 

 distinct molluscan faunas, which recur with irregular alternations. 

 One fauna is characterized by the Unio-]ike genera Carbonicola 

 and Anthracomya, and the Dreissensia-like Naiadites ; the other 

 by Pterinopecten papyraceus, Posidoniella, with many species of 

 Cephalopoda : and the two never mix. 



1 Trans. Geol. Soc. ser. 2, vol. v (1840) pp. 442-44, 490-93, & pis. xxxix-xli. 



2 Trans. Manch. Geol. Soc. vol. xxi (1891-92) pp. 364-400 & pis. i-iii. 



3 Quart. Journ. Geol. Soc. vol. xxxiii (1877) pp. 613-50. 



