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The Mendip Hills, as you know, form the southern boundary 
of the Bristol Coal-field, but our distinguished President, 
Sir Wm. Guise, Mr Erxeriper, and myself, were able two or 
three years ago, to gather proofs from the rocks of Carrington — 
Park, near Bridgwater, that those rocks, which had previously 
been regarded as Devonian Limestone, were, after all, the Car- 
boniferous Limestone, though in a highly crystalline condition, 
and very sparse of fossil remains. Being, however, genuine 
Mountain Limestone, they show almost certainly the existence 
of a Coal-field south of the Mendips. 
My object in referring to this is to recall your attention to 
a fact that was proved by our friend Mr Ernerinesr and the late 
Mr Cuartes Moors, of Bath, beyond all question, namely, 
that the Mendips were lifted after the deposition of the Coal 
Measures, but prior to the deposition of the Secondary Rocks; 
and that when those Hills were thrust up by the volcanic force 
that in some portions has pushed the lava right through the 
Limestone and Old Red Sandstone, the whole country to the 
north, and possibly to the south as well, was thrust forward. 
We know at Radstock, five miles north of the Mendips, this 
thrust has given Lady Wa.preerave a double deposit of the 
Radstock or Upper Series of Veins. We must, however, I think 
look for the force that has thrust the Kingswood Coal-field 
over itself at a nearer point than the Mendip Hills; and I think 
if you will look at the enormous development of Carboniferous 
Limestone at Blackdown, Bourton, and in that district, we shall 
see the seat of the force that has caused this displacement. 
It is singular and exceedingly interesting to note the effect 
of this thrust to which I am calling attention. If you will look 
at the map you will see that south of where we stand the river 
Avon has been pushed a mile to the north out of its natural 
course—by the same force (as I think) that has thrust the Coal- 
field over itself. And I happen to know that two or three miles 
below Bristol the level course of the seams of Coal, in the 
Coal-field, has been turned almost at right angles to its regular 
course by the same upheaval of Carboniferous Limestone and 
the displacement caused thereby; and the level course of the 
Ries 
