A CHAPTER IN THE PHYSICAL GEOGRAPHY OF THE PAST. 53 
we find the old Carboniferous beach resting upon the old Red 
Sandstone, and, to a great extent, derived from its waste. From 
the thinning out of all the beds above this, there is the strongest 
possible evidence that, across a line drawn from the Firth of Tay 
to the extreme North of the Island of Arran, the shore conditions 
continued for a very long period in Lower Carboniferous times, 
and that the land rose rapidly North of this line, in the region of 
the Scotch Highlands, to a much greater height than it does at 
the present time. 
In Ireland the Carboniferous Limestone is strongly repre- 
sented in Clare, Tipperary, and Queen’s County, its greatest 
development being only about half a degree of latitude further 
south than its greatest development in our own Northern 
Midlands. Here, just as with us, the limestone shows the same 
tendency to give place to mechanically formed deposits, 7.¢., sand- 
stones and shales, further towards the north and north-west, 
indicating, as with us, the direction in which the old land lay. 
That the western portions of Donegal, and of Connaught, formed 
part of this coast there is a great deal of evidence to show, and 
it is probable that the western portion of County Kerry was also 
above water. 
Around the old Silurian Rocks of our Lake District there are 
found thick uneven deposits of Conglomerate and Sandstone, 
belonging to the base of the Carboniferous, and, from: their 
irregularity and the rapid way they thin out, it is evident that they 
were beach deposits banked around an island in the Carboniferous 
Sea. There are also similar deposits in the southern part of the 
Isle of Man. 
Having traced the Mountain Limestone of the deep water of 
Central Derbyshire to the north and north-west shore of the sea 
in which it was deposited, we will retrace our steps once more to 
- the Derbyshire district, and ascertain what becomes of this 
massive limestone when followed southwards. 
The southern prolongation of the limestone of the Weaver 
Hills plunges, as we have seen, beneath the more recent New 
Red Measures near Ashbourne, and we see nothing more of it 
