Chap. 12.] GEOLOGY, BOTANY, fco. 249 



Carboniferous Eocks of the district : — 

 Upper Carboniferous . .Millstone Grit (part of). 



Lower Do i ^<""^d^^^ Rocks. 



( Carboniferous Limestone. 



These admit of further sub-division as follows : — 



Millstone Grit Series j l^"^^^^^ (Kinderscout). 



("Upper Yoredale (Pendle Grit). 



JBowland Shales. 

 Lower Yoredale Grita. 

 I Shales and impure Limestone, 

 LCarboniferous Limestone. 



By the above table it wiU be seen that the lowest and therefore oldest 



member of the system in this district is the Carboniferous, or, as it is 



sometimes termed. Mountain Limestone. It is a massive blue-grey, 



often crystalline, usually fossilLferous rock. In this district it probably 



rests on the upturned edges of Silurian beds. It occurs in a continuous 



band along the north-west flank of the Longridge Fell, and is quarried 



at Thornley and other places in the vicinity. Farther from home it 



may be seen on the banks of the Loud, on the banks of the Hodder, 



from south of Greystoneley to Whitewell, and at Chaigley. 



During its formation nearly the whole of the British area was sub- 

 merged. The nearest mainland to the north of our district was a 

 coastline trending in the direction of a Hne drawn from the north-west 

 coast of Ireland to near Aberdeen, and forming only a portion of the 

 coastline of a large continent extending to, and probably including, 

 Greenland. To the south a long and narrow ridge extending from the 

 east coast of Ireland to "Wales, thence across England to the coast of 

 Norfolk, and probably across the North Sea to Germany, separated us 

 from the southern counties, which were also submerged. 



The exact period of this submergence it is impossible even to estimate 

 but that it must have been of long duration is proved by the fact that 

 during the submergence 4,000 feet of massive limestone was formed 

 from the exuvise of marine organisms, myriads of which may be found 

 embedded in the stone apparently unaltered in form, and, in the case 

 of some of the shells of the mollusca, even retaining their coloui-ed 

 markings. 



