AN OUTLINE OF THE BEARINGS 
OF THE 
PHYSICAL GEOGRAPHY OF THE COUNTY 
UPON ITS VEGETATION. 
Tlie superficial area of the county is stated at 5836 square miles. That 
of the whole of Britain is about 90300 square miles, and yet we have seen 
that within the limits of Yorkshire, three out of every four vascular species 
which the island produces have been ascertained to occur. If, however, 
the range of climate and physical character embraced within the area of 
the county was less extensive, the number of species which it furnishes 
would be decreased in proportion. As the natural result of its varied 
structure and the varied elevation of different parts of its surface, in its 
flora, groups of plants of austral and alpine distribution, with the various 
intermediate gradations, meet and mingle together. The broad and fertile 
central vale and its ramifications, where the annual temperature is the 
normal effect of latitude, and does not differ materially from that of a 
considerable part of the midland counties of England, afford a flora com- 
paratively luxuriant in species, typically southern, and essentially English 
in its characteristic features. Amongst the wide extent of the broad 
ranges of barren moorlands, where the climate from the elevation of the 
surface corresponds with that of the lowland provinces of Scotland, a 
vegetation of a more northern stamp finds supplied the suitable condi- 
tions for its existence. Whilst round the elevated peaks of the great 
central ridge of the island, cluster those more hardy and arctic species 
(supposed to be the vestiges of the flora of the pre-glacial epoch) which 
find in Britain their head quarters amongst the Grampians of Perth ,and 
Forfar, and Aberdeen. 
The author of the “ Cybele Britannica” lias considered the surface of 
Britain as subdivided into two climatic regions.* The boundary between 
* Vide “ Cybele Britannica,” vol. i. pp. 19 — 43. 
