Now to make that 3000 feet of hard rock, what must have happened?
The sea-bottom must have sunk, slowly no doubt, carrying the coral-reefs down with it, 3000 feet at least.

And meanwhile sand and mud, made from the wearing away of the old lands in the North must have settled down upon it.

I say from the North--for there are no fossils, as far as I know, or sign of life, in these rocks of mill-stone grit; and therefore it is reasonable to suppose that they were brought from a cold current at the Pole, too cold to allow sea-beasts to live,--quite cold enough, certainly, to kill coral insects, who could only thrive in warm water coming from the South.
Then, to go on with my story, upon the top of these mill-stone grits came sand and mud, and peat, and trees, and plants, washed out to sea, as far as we can guess, from the mouths of vast rivers flowing from the West, rivers as vast as the Amazon, the Mississippi, or the Orinoco are now; and so in long ages, upon the top of the limestone and upon the top of the mill-stone grit, were laid down those beds of coal which you see burnt now in every fire.
But how did the coral-reefs rise till they became cliffs at Bristol and mountains in Yorkshire?
The earthquake steam, I suppose, raised them.

One earthquake indeed, or series of earthquakes, there was, running along between Lancashire and Yorkshire, which made that vast crack and upheaval in the rocks, the Craven Fault, running, I believe, for more than a hundred miles, and lifting the rocks in some places several hundred feet.

That earthquake helped to make the high hills which overhang Manchester and Preston, and all the manufacturing county of Lancashire.