Vol. 57.] PENDLESIDE GKOUP AT PENDLE HILL, ETC. 377 



There is consequently a well-marked stratigraphical aud palseon- 

 tological break in the Carboniferous succession, which comes on in 

 Scotland at the top of the Upper Carboniferous Limestone Series, in 

 Northumberland and Northern Yorkshire at the top of the Yoredale 

 Series, in Southern Yorkshire and Derbyshire at the top of the 

 Carboniferous Limestone massif. 



Palaeontology shows that for purposes of classification a twofold 

 division of the Carboniferous rocks obtains: one fauna with 

 subfaunas characterizing the lower series, and another being cha- 

 racteristic of the Pendleside Group, Millstone-Grit Series, and Lower 

 Coal-Measures. 



The Pendleside Group consists of shales and limestones, with 

 occasional sandstones and mudstones. The limestones are peculiar 

 in character and form, and can never, even in small specimens, be 

 mistaken for the white limestone of the massif. These limestones 

 are largely lenticular, the limestones being very local : sometimes 

 well-bedded limestones gradually pass into calcareous shales, or into 

 shales with bullions of calcareous matter. Fossils are most plentiful 

 in those localities where the limestones are thin and concretionary. 

 Chemical and physical facts in connection with these limestones 

 will be dealt with in another section, but the immense quantity of 

 carbonaceous matter and hydrocarbons in the shales and also in the 

 limestones is to be noted. The shales indeed are black with coaly 

 particles and detrital plant-remains. These particles must have come 

 from either terrestrial or marine plants, and in both cases indicate 

 proximity to a shore. 



The further facts of the distribution of Glyphioceras spirale and 

 Posidonomya Becheri, set forth in the foregoing pages, open up the 

 wide question of the age of the Culm-beds of Devon and Germany ; 

 and in reference to this point the discovery of radiolaria in the 

 limestones of the Pendleside Group by one of us is important. 



III. Paleontology. 



In the Carboniferous-Limestone areas of Staffordshire, Derbyshire, 

 Southern and Eastern Lancashire, and South-western Yorkshire, 

 there exist two distinct faunas : one, the lower, is found in the 

 Carboniferous Limestone, while the other characterizes the Upper 

 Limestone-Shales, the marine bands of the Millstone-Grit Series, 

 and the Lower Coal-Measures. 



The basement-line of the upper fauna is the junction 

 of the massive limestone with the dark shales which 

 succeed it. At certain localities, Tissington in Derbyshire, 

 Pendle Hill and Downham in Lancashire, at Park Head Quarry 

 (Lothersdale) and Poolvash (Isle of Man), the abrupt change in the 

 fauna may be seen; but in many other places, where the lithological 

 change, which accompanies the palseontological one, is clearly visible, 

 no fossils have been obtained by us at the actual junction. Thus at 

 the London & North-western Railway-cutting north of Doveholes, 

 the two series are seen in contact ; yet no fossils are noticed in the 



