484 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 19, 



There is abundant evidence in this district that it is not coloured 

 by the rocks on which it lies, but by the rocks over which it has been 

 pushed. Where the ice-sheet has been passing for some distance 

 over grey rocks (fig. 3) you may find grey drift upon them ; and if, 

 further south, red rock comes on, you will still find grey drift upon it. 

 But if the red rock continue for some distance southwards, you will 

 see the red drift coming in beneath the grey, and the latter tailing out 

 as the former increases in bulk and importance. If, again, conti- 

 nuing your section south, there is a change from red rock to grey, 

 again you will have the red drift resting upon the grey rock for 

 some distance, until the grey drift rises from the rock and intervenes, 

 and so on, the waste product being always on the lee side of the 

 rock producing it. There are several instances of this in the district. 

 Thus, in the valley of the Lune, north of Kirkby Lonsdale, are two 

 long patches of Old Eed Sandstone. Further south, in the direction 

 of the ice-movement in Leek Beck, are Coal-measures consisting for 

 the most part of grey rocks, such little red colouring as they do 

 possess being probably derived from the overlying drift. This is 

 almost as red as the Old Red Sandstone, certainly very much redder 

 than the Coal-measures on which it rests, so that the latter cannot 

 be the source whence its colour was derived. There can be little doubt 

 that this drift has passed over the Old Eed Sandstone higher up the 

 valley. Again, the patch of Permian south-east of this has acted in 

 a similar way upon the drift which lies immediately to the south of it. 



In the nibble valley, near Clitheroe, is a patch of red rocks sup- 

 posed to be of Permian age. It lies about 20 miles to the S.S.E. 

 of the last-mentioned ; and no other red rocks exist in the country 

 between; grey Till lies upon it. About half a mile south of its southern 

 boundary is a section in Barrow Brook, showing at the base grey 

 Carboniferous shale ; on that is grey Boulder- clay, and above it red 

 clay ; over this, again, is grey Boulder- clay, the line between the two 

 being very distinct. It is probable that we have here first the Till 

 from the grey rocks south of the Permian, then that from the Per- 

 mian, and lastly that from the grey rocks on the other side of the Per- 

 mian. There is no other red rock which could give the colour but 

 this Permian ; the next nearest rock of that colour is some Trias in 

 the nibble, 7 miles or more to the south-west. All these facts point 

 to the southern movement of the ice-sheet. 



Again, on the Trias just mentioned, in the Kibble below Stub- 

 bin's Wood, on the left bank is a fine section including Pebble-beds, 

 Till, Middle Sands and Gravel, and Upper Boulder-clay. The Trias 

 is faulted down to the south-west against grey Carboniferous rocks. 

 The Till on this Trias is grey ; but further to the south you have 

 grey and yeUow Carboniferous rocks with red Till reposing on them. 

 The diagram (fig. 3) is a sketch section embodying these observations. 



If we allow, for the sake of argument, that there was at one time 

 an ice-sheet over the whole or nearly the whole of this district, and 

 that it slowly disappeared, we must admit that each piece of ground so 

 covered must at one time have been at the edge of that sheet, and 

 that there would be a time when at any particular spot the ice 

 would be losing strength to such an extent that it could no longer 



