CHAPTER I. 
Series of Yorkshire strata. Geological description of the eastern part 
of the county. 
Yorkshire is one of the few counties of England which are defined 
by natural boundaries. On the west it reaches, and in some places 
extends beyond, the great summit ridge of the island; the Tees is 
its natural limit on the north, the Dun for a great length on the south, 
and on the east it is washed by the German ocean. Its area is divided 
into several obvious sections, distinguished alike by topographical fea- 
tures and geological structure. Along the middle of the county, from 
north to south, runs a wide level vale, filled with gravel, deposited 
on the upper red sandstone. From beneath, rises towards the west 
an elevated undulated tract, of carboniferous and calcareous rocks, which 
ascend to the summits of Micklefell, Ingleborough, and Pen die Hill ; 
whilst above, on the east, appear the uniform ranges of the chalk and 
oolite. The hilly western tract is grouped in two portions : the district 
south of the Aire, in which, generally, sandstones and shales with coal 
abound ; and the more elevated region north of that river, whose ro- 
mantic dales are sunk into the mountain limestone, and whose hills 
are capped by the low r er members of the coal series. 
I he eastern part of Yorkshire may be topographically considered in 
five divisions — Ihree of these are conspicuous from their elevation ; viz. 
the open round-fronted wolds of chalk in the south, the flat-topped 
ranges of oolite in the middle, and the more mountainous groups of 
shale, sandstone, limestone, and coal, which form the northern moor- 
lands ; two are wide, level tracts : viz. the vale of Pickering, which 
separates the chalk wolds from the oolitic hills, and Holderness, which 
