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abound, none occur in the Edinburgh coal-field, although they were 
abundant in that district during the earlier part of the Carboniferous 
period. 
The system of parallel faulting of the Pentland Hills is also 
worthy of notice, as accounting for the small development of Lower 
Carboniferous strata on the east of the chain, and their great expan- 
sion to the west. The highly inclined character of these strata along 
the east side of the hills (some being quite on edge, hence called 
“ Edge-coals”), arises from the downthrow of the whole coal-field 
against the older rocks of the chain. A detailed description of the 
sheet from the geologists before named is at present in the press. 
The attention, not of geologists only, but of men of science in 
several departments, has, during this and the preceding year, been 
fully awakened to the importance of a discovery which is really of 
much older date— viz., that flint implements, the work of man, are 
found in beds of drift gravel associated with the bones of the last 
generation of the great extinct mammalia. The full significance of 
this fact is only now being fully recognised, and many of the con- 
clusions which it may tend to establish are subject to much doubt, 
and will probably form the subject of increasing controversy. But 
it is only necessary to have a clear idea of the facts as they have 
been now ascertained, to see that one conclusion at least is placed 
beyond all question — viz., that great physical changes on the surface 
of the earth, and these, in part at least, effected by the agency of 
water, have taken place since the creation of man. 
Whether this conclusion carries the creation of man farther back 
than had commonly been supposed, or whether it merely brings 
nearer to us than we had before conceived, the last great changes 
which have produced the existing surface, is the main question on 
which debate arises. As geology gives no certain data for com- 
puting positive, but only relative time, this question is necessarily 
involved in much obscurity. But there are certain limits within 
which, after all, the controversy is confined. It is well to observe 
that, according to the principle on which geological times and epochs 
are classified, the human epoch remains, after these discoveries, very 
much where it stood before. It is true that many of the large 
animals, with which the traces of man seem to be connected, are 
now extinct ; but a very much larger number are still living. The 
