190 GEOLOGICAL HISTORY. 



Cornus suecica In the vicinity of Pickering and Scarborough. 



Trientalis europaea. Hambleton Hills, Swill Hill near Halifax, Rume- 



ley's Moor, Holwick in Teesdale. 



Potentilla alpestris. In the north-western region about Malham and 



Cronkley. 



Sedum villosum . . . Weathercote Cave, Malham, Baldersdale, &c. 



Salix herbacea On Ingleborough. 



My friend Mr. Backhouse, by whom the prolific region of 

 Teesdale has been repeatedly explored, has found Myosotis sua- 

 veolens flowering in abundance on the high limestone at the east 

 end of the top of Mickle Fell at the end of June. Polygala 

 uliginosa, Reich., has also rewarded his re-examination of the 

 botanically celebrated Cronkley Scar. These are also Scandina- 

 vian plants. 



The localities of these plants, it will be observed, lie in the 

 elevated parts of the north-western and north-eastern districts of 

 Yorkshire ; but, excepting perhaps Salix herbacea, they are not 

 confined to the highest parts. These same elevated districts are 

 as remarkably deficient in land mollusca as are the mountainous 

 tracts of Scandinavia ; they do not contain all the species of our 

 actual fauna and flora, or even a large proportion of it, nor is 

 it conceivable that they ever did contain them, so as to be the 

 source from which they spread over the islands. 



Therefore, although we admit that the glacial inundation did 

 not cover all our land, and that some species may have been 

 saved from it on the mountains, this does not the less render it 

 necessary to suppose a second migration for the replenishing of 

 the lower grounds with species which cannot be traced to those 

 mountains. Now the greater part of our flora and fauna is in 

 this condition. It is essentially allied to, or rather identical with, 

 the plants and animals of Germany, and its general distribution, 

 not in Yorkshire only, but in all the British Islands, seems to 

 require positively the admission, that after the glacial period 

 the bed of the German Ocean (which had been a glacial sea) 

 was raised above the water so as to constitute a dry-land com- 

 munication with the east and south-east. 



