6 NELSON AND TAYLOR : ON YORKSHIRE MOLLUSCA. 



Kirkburton, thence water-shed line by Shelley, Denby Grange, 

 Midgley, Woolley Edge, Staincross, Notton and Ryhill to Crofton 

 Station. 



13. Airedale. — "Upper" and "Lower Calder" boundary 

 from I^ancashire to Castleford, Roman road to Micklefield^ "Vale 

 of York" boundary to Arthington, and water-shed to Ilkley Moor, 

 thence turning to Keighley Moor and Lancashire Border. 



14. Malhamdale. — A watershed district, being the upper 

 portion of Airedale, separated from District 13 by the water-shed 

 line from Ilkley Moor to Keighley Moor. 



15. Wharfedale. — The basin of the Wharfe, separated 

 from the "Vale of York" by the railway at Arthington and Weeton. 



16. Nidderdale. — Separated from the "Vale of York" 

 by the railway at Knaresbro'. 



\7. Wensleydale. — Separated from the "Vale of York" 

 by the Knaresbro' and Boroughbridge Railway. 



18. Swaledale. — Separated from the "Vale of York" by the 

 rail from Coxwold to Boroughbridge. 



19. Upper Tees. — The upper portion of the Tees basin 

 as far East as Hornby. 



20. Lower Tees. — The lower portion of the Tees basin; 

 also including all the country drained by the streams falling into 

 the sea North of Flat Scar, near Saltburn. 



21. Eskdale. — The country drained by streams between 

 Flat Scar and Old Peak, South of Robin Hood's Bay. 



22. Upper Derwent. — Separated from the central 

 district by the rail from Coxwold to AVharram — also includes the 

 coast line from Old Peak to Beighton. 



23. Chalk Wolds.— East bank of Market Weighton 

 Canal to Market Weighton, and rail to Hayton, thence "Vale of 

 York" boundary to Wharram, thence road to Sledmere, Foxholes, 

 Wold Newton and Beighton to sea. For East boundary see next 

 district. 



24. Holderness. — Separated from District 23 by the rail 

 from Bridlington Quay to Lowthorpe and the West bank of the 

 river Hull from Lowthorpe to Hull town, 



