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.