PRE-CARBONIFEROUS FLOOR OF THE MIDLANDS. 
89 
area of equal dimensions upon the surface of the globe. The 
axis of greatest elevation now lies to the west, running 
through the Lake District and Wales. From this it results 
that the strata have a general dip or slant to the south-east, 
the oldest rocks forming the actual surface of the ground in 
these western tracts, but being covered over and concealed 
by newer rocks as we proceed eastward. If all the beds of 
rock lay in regular undisturbed sheets, as they must have 
originally been deposited on the sea bottom, we, in the 
Midlands, could never hope to discover any Pre-Carboniferous 
strata at the surface, for they would be below thousands of 
feet of later-deposited rocks. But, during the upheavals 
and depressions which the British Isles have experienced 
—and they have undergone many changes of level, amount¬ 
ing to thousands of feet—the rocks have cracked, and the 
beds along one side of the crack or “ fault” have been 
elevated or depressed as the case may be. Then lateral 
pressure, whose effects have but lately been recognised on a 
grand scale in the Highlands of Scotland, has thrown the 
rocks into great folds, having crests and hollows. Follow¬ 
ing these earth movements, the agents of denudation 
have swept away the material from the “ upthrow ” sides 
of the faults, and from the crests of the earth-folds, and thus 
the wonderful variety of rocks which characterises our 
country has been produced, and we are able to find strata 
of the same age and of similar lithological characters to 
those of Wales and the Lake District within a short distance 
of Birmingham and Leicester. 
But to discover and identify every exposed area of these 
old rocks in the Midlands our search must be both keen and 
careful, and we must have a competent knowledge of what to 
look for, gained by the study of typical sections and specimens. 
Although the geological surveyors are instructed to walk along 
the four sides of every field and to examine every patch of 
rock—and I can bear testimony to their hard and generally 
excellent method of work—yet they missed the true inter¬ 
pretation of many important exposures, and it is clear that 
in the present position of British geology more good will 
result from the close study of a limited area than from 
occasional scamperings over a wide region. I remember 
well, many years ago, how I walked over all Leicestershire 
to find an outcrop of the Rhaetic beds, which I discovered at 
last in a brick pit close to my own back door! 
We will consider, in the first place, those Midland areas 
in which the old Pre-Carboniferous strata actually rise to 
the surface; secondly, the places where they have been 
