XVI 
INTRODUCTION. 
welldale, and Littondale ; again crossed Hardflask and Malham moors ; 
walked down Airedale to Skipton ; and by Bolton, Blubberhouses, and 
Harrogate, traced the divisions of the millstone grit. 
In the course of so many pedestrian journeys most of the high 
mountains have been ascended, and nearly every valley explored; the 
thicknesses of the strata having been ascertained by above one thou- 
sand barometrical observations. 
I hope the preceding sketch of my proceedings will be thought 
to justify my publication ; the nature of the subjects investigated, 
the necessity of close personal investigation of so many hills and dales, 
combined with that want of leisure, which so fatally retards the progress 
of men devoted to science, must be my apology for the long delay 
of its appearance. 
I turn with pleasure to record the assistance which has been fur- 
nished me by several friends, whose names are not mentioned in the 
preceding pages. The mines of Greenhow hill were described to me 
on the spot by Mr. Nathan Newbold and Mr. Watson ; Mr. Barratt 
supplied me with notes of those at Grassington, Mr. Stagg obligingly 
answered some queries concerning the mines which are under his able 
direction in Teesdale, and additions to my knowledge of the veins of 
Aldstone moor and the neighbouring districts were received from Mr. 
Sopwith, Mr. N. Wood, Mr. H. L. Pattinson, and Mr. Wm. Hutton. 
Notices of the limestones of Craven have at different times been commu- 
nicated to me by Mr. Preston of Flasby, and Mr. Hamerton of Hellifield 
Peel; Mr- Yorke of Bewerley afforded me every facility for my in- 
quiries in Nidderdale ; Mr. Wheeler of Barnard Castle, Mr. Rutter of 
Middleton in Teesdale, Mr. Jonathan Otley of Keswick, and the late 
Mr. Bland of Hilton, have given me local information. My best thanks 
are due to Mr. Hodgson of Lancaster, for prompt and complete informa- 
tion respecting the curious coalfield of Ingleton and Burton. 
I am greatly obliged by the prompt attention of Mr. Gibson of 
