Oh, what hanging-woods, and churches; and such great houses, and pretty cottages and gardens—all in this narrow crack of a valley!
Ay. Old Father Thames is a good landscape gardener, as I said. There is Basildon—and Hurley—and Pangbourne, with its roaring lasher. Father Thames has had to work hard for many an age before he could cut this trench right through the chalk, and drain the water out of the flat vale behind us. But I suspect the sea helped him somewhat, or perhaps a great deal, just where we are now.
The sea?
Yes. The sea was once—and that not so very long ago—right up here, beyond Reading. This is the uppermost end of the great Thames valley, which must have been an estuary—a tide flat, like the mouth of the Severn, with the sea eating along at the foot of all the hills. And if the land sunk only some fifty feet,—which is a very little indeed, child, in this huge, ever-changing world,—then the tide would come up to Reading again, and the greater part of London and the county of Middlesex be drowned in salt water.
How dreadful that would be!
Dreadful indeed. God grant that it may never happen. More terrible changes of land and water have happened, and are happening still in the world: but none, I think, could happen which would destroy so much civilisation and be such a loss to mankind, as that the Thames valley should become again what it was, geologically speaking, only the other day, when these gravel banks, over which we are running to Reading, were being washed out of the chalk cliffs up above at every tide, and rolled on a beach, as you have seen them rolling still at Ramsgate.
Now here we are at Reading. There is the carriage waiting, and away we are off home; and when we get home, and have seen everybody and everything, we will look over our section once more.
But remember, that when you ran through the chalk hills to Reading, you passed from the bottom of the chalk to the top of it, on to the Thames gravels, which lie there on the chalk, and on to the London clay, which lies on the chalk also, with the Thames gravels always over it. So that, you see, the newest layers, the London clay and the gravels, are lower in height than the limestone cliffs at Bristol, and much lower than the old mountain ranges of Devonshire and Wales, though in geological order they are far higher; and there are whole worlds of strata, rocks and clays, one on the other, between the Thames gravels and the Devonshire hills.
But how about our moors? They are newer still, you said, than the London clay, because they lie upon it: and yet they are much higher than we are here at Reading.
Very well said: so they are, two or three hundred feet higher. But our part of them was left behind, standing up in banks, while the valley of the Thames was being cut out by the sea. Once they spread all over where we stand now, and away behind us beyond Newbury in Berkshire, and away in front of us, all over where London now stands.