Marr : The Rigidity of North-west Yorkshire. 71 



has cut a deep channel in the Ingletonian rocks to the north 

 of the town of Ingleton. At the bottom of this channel is in 

 one place an accumulation of boulder-clay, formed subsequently 

 to its erosion. We seem here to get evidence of an important 

 climatic oscillation, though how important can only be settled 

 by detailed work. 



Turning now to plant distribution, it is, I believe, generally 

 recognised that the tract has formed a barrier dividing eastern 

 Germanic and western Atlantic assemblages, though here I am 

 speaking of a subject of which I know little. 



It is a district where much still remains to be done as 

 regards plant-ecology, Pleistocene and recent. The researches 

 of F. G. Lewis have given us a starting point for the study of 

 Pleistocene plants, and their bearing upon climatic oscillations. 

 The district, owing to its elevation and the abundance of 

 calcareous rock, is exceptionaly rich in alpine plants. I was 

 grieved to see the late Dr. J. G. Baker throwing doubts upon 

 the claim of the most beautiful of these, Gentiana verna, but 

 still many genuine cases remain. 



It is interesting to see the effect which changes in the 

 remote past have exercised upon recent occurrences. I pointed 

 out that the rigid block caused the injection over a wide area 

 of the Whin Sill. The latter produced the saccharoidal lime- 

 stone, which forms so favourable a soil for xerophilous plants, 

 and accordingly we find Helianthemum canimi, one of the few 

 native alpines with hairy leaves flourishing upon this limestone 

 on Cronkley Fell. 



Lastly we may turn to the effects of the rigid block on the 

 distribution of man. 



In historic times it has throughout acted more or less 

 effectively as a barrier separating the men of the north-east 

 from those of the north-west, and even in these days of rapid 

 transit, the effects are not entirely obliterated. In prehistoric 

 times, it was probably even more marked. In the border- 

 period, the Neo-celtic type of art linked to that of Ireland seems 

 to be prevalent on the western side. In Neolithic or probably 

 bronze times, the curious ripple-flaking akin to Scandinavian 

 workmanship is confined to East Yorkshire, and certain 

 stone implements of Cumberland and Westmorland have an 

 individual fades. 



But though the rigid block has acted as a barrier between 

 east and west, it has had an occupation of its own. It had its 

 own glaciation, its own flora, and its own early human inhabi- 

 tants, and of the latter there is yet much to be learnt. Was it 

 ever occupied in Palaeolithic times ? Aurignacian man has 

 been claimed as inhabiting the Victoria Cave, Settle, and it is 

 quite possible that we may ultimately find relics of, at any 

 rate, Upper Palaeolithic man. 



1921 Feb. 1 



