X 
INTRODUCTION. 
disclosed by topographical research, can be united in a general history, 
and referred to laws of causation. 
These advantages, combined with others depending on large area 
and geographical position, appear to justify the adoption of the York- 
shire series as a general type or standard of comparison for the limestone 
deposits of Europe. 
I must not hope that in working out the magnificent problem 
attempted in this Volume, my efforts have been uniformly success- 
ful ; but I am anxious to escape the imputation of having undertaken 
a task of great difficulty and importance without adequate preparation 
or peculiar advantages. 
In 1819, I made, under the guidance of my Uncle, Mr. Smith, 
my first examination of the limestone of Yorkshire, and learned from 
Mr. Francis Gill of the Auld Gang Lead Mines the succession of the 
strata in Swaledale, for comparison with the very different series I had 
before seen at Bristol, in the forest of Dean, and near Pontypool. 
In 1821, I made an active pedestrian tour of four months in the 
North of England; passing through the limestone tract of Derby- 
shire, and over the summit ridge of millstone grit into Yorkshire at 
Peniston ; thence by Halifax, and the vale of Todmorden to Burnley, 
Colne, Skipton, and Settle. From Settle to Kirby Lonsdale, the line 
of the great Craven fault was attentively surveyed ; at Kendal Mr. 
Todhunter’s museum was consulted and Underbarrow scar examined. 
My route then led me to the limestone of Ulverston, and Egremont, 
and, in various walks round the lake district, the limestone border was 
examined at Lowther, Orton, and Kirby Stephen. 
I crossed three times the Penine chain between Penrith and Aldstone 
moor, and spent some time in the examination of that interesting 
district ; passed by Hartley burn to Gilsland wells ; followed the basaltic 
line of the Roman wall ; and turned by the North Tyne and the valley 
of the Reed toward Carter fell. After skirting the Cheviot beyond 
