LITHOLOGY. 65 



CHARACTERISTICALLY XEROPHILOUS SPECIES — ConthlZted. 



Local and less abundant species : 



Anemone Pulsatilla 

 Draba muralis 

 Helianthemum canum 

 Linum perenne 

 Hippocrepis comosa 

 OnolDrychis sativa 

 Potentilla vema 



Galium erectum 

 Aspenila Cynanchica 

 Inula Conyza 

 Senecio campestris 

 Carduus acaulis 

 Orobanche rubra 



Thymus Chamjedrys 

 Calamintha Nepeta 

 Epipactis ovalis 

 Ceterach officinarum 

 Polypodium 



Robertianum. 



Of these forty-three species, fifteen are restricted to the West 

 of the Central Valley and four to the East, but the remaining 

 twenty-four grow both upon the east and the west of it. Of the 

 distribution of the latter that of Aquilegia vidgaris will afford a 

 fair average illustration. 



So far as known to me the Wild Columbine grows in North 

 Yorkshire as follows, excluding from consideration two or three 

 stations where it is plainly a garden escape. Amongst the 

 western hills in Swaledale in woods at the Round Howe and on 

 the north side of the river near Applegarth, and in the Yore 

 district in Fossdale Woods and Shaw Gill, Hardraw, in all these 

 cases- amongst the scars of the Yoredale Limestone ; and also 

 in Wensleydale by the Yore side about the Aysgarth rapids 

 upon the Lower Scar Limestone. From the tract underlaid by 

 the Millstone Grit series it is altogether absent. Where the 

 Magnesian Limestone comes to the surface it grows in woods 

 by the Wharfe side at Thorparch. It overleaps altogether the 

 New Red Sandstone of the Central Valley and is absent also 

 from the tracts underlaid by the Lias and the Inferior Oolite. 

 Amongst the woods of the calcareous embankments of the 

 hills of the Middle Oolite it grows plentifully in Yowlasdale, 

 Beckdale and several other places about Helmsley and Hawnby 

 and Pickering, in the Howardian tract in several stations, and 

 in the dale of the Derwent near Hackness. From the Vale of 

 Pickering it is altogether absent. 



Hot. Trans. Y.N.U., Vol. 3. F 



