A CHAPTER IN THE PHYSICAL GEOGRAPHY OF THE PAST. 39 
angles of dip, and fossil contents, finds, it is true, a keen and 
vivid enjoyment in such work, but if he is of a philosophical turn 
of mind, he will place but little scientific value upon. such obser- 
vations, when they are regarded as mere isolated phenomena ; 
but when a large mass of facts has been accumulated and systema- 
tized, it becomes possible by a comparison and correlation of 
results, and by the application of strict methods of reasoning, to 
make out the order of past events, and to read by the light of the 
present the physical changes which this world of ours has under- 
gone in ages long past. This is, indeed, the highest aim of 
_ geology, which has been well defined as the “physical geography 
of the past,” and I think I shall do well by attempting to show 
you something of the methods by which this re-construction of 
old world features is accomplished, and by applying them to the 
elucidation of some of the past conditions of the portion of 
Central England in which we live. The period which I have 
selected for this purpose is that in which were laid down the great 
mass of the Carboniferous Rocks, rocks including the Mountain 
Limestone and the Coal Measures. Owing to their vast super- 
ficial exposure in Great Britain and Ireland, and to the manner in 
which they have been explored for their mineral wealth, we have, 
perhaps, in the Carboniferous Rocks a greater accumulation of 
important facts to work upon than we have in any other system. 
Before attempting to throw any light upon this chapter in the 
ancient physiography of our Midland District, I must, in the first 
place, call your attention to the existing conformation of the 
surface, and to the close connection there is between the nature 
of the underground rocks and the features of the country as now 
presented to us. 
If we look at any good physical map of England, we notice, 
running almost down the centre of the Northern part of the 
country, a broad range of hills which forms a great water-parting, 
from the western side of which the streams run into the Irish Sea, 
and from the eastern into the North Sea. This broad ridge of 
high ground—one of the most striking natural features of our 
country—is known as the Pennine Range, and has been aptly 
