14 
Again, the mountain limestone of Derbyshire is a part of 
the carboniferous series which certainly belongs to the Coal 
Field of Yorkshire ; it does not basset out from under the Lan- 
cashire but the Yorkshire Field, and therefore in fact belongs 
to us. It possesses along with its extensive suite of fossils 
(of which 400 different species are contained in the lower scar 
limestone) the very highest geological interest. A collection 
of fossils from this region, compared with one from the mag- 
nesian limestone, both of which we have the finest opportu- 
nity of collecting, would at once show how many species are 
similar, and if any at all are identical. And the details of the 
Derbyshire limestone being embodied in the section, would 
make it of value not only to the two Societies, but to all who 
study the science. Again, there is a system of transverse 
and longitudinal valleys in the Yorkshire Coal Field to which 
none other in the British Isles are exactly analogous; a 
study of these valleys, with their relation to the Derbyshire 
axis, the passage of large bodies of water from the west, 
and the diluvium which they severally contain, would well 
repay the labour bestowed ; for, if a true theory of the forma- 
tion of these valleys could be made, it would afford a clue to 
the interpretation of the mode of action of the forces which 
elevated our continents. Those within the area of the Coal 
Field scarcely contain any diluvium, but those of Derbyshire 
abound with pebbles left above the highest flood-mark. The 
line of the proposed section follows one transverse valley of a 
tributary of the Dearne, crosses one slight escarpment, thence 
to the source of the Don, and keeps along the valley of 
Woodhead for a distance of 1 0 miles, entirely avoiding the 
numerous characteristic valleys of this coal field. 
It must be recollected also, that there is another sister- 
portion of these two Coal Fields in Derbyshire. The Don 
section would at once apply and be a key to the stratification 
of that country. Surely we are as much connected with that 
Coal District as with the one of Lancashire. Can we gain 
