And what is that in the air? A bridge? Yes--that is the famous Suspension Bridge--and a beautiful work of art it is. Ay, stare at it, and wonder at it, little man, of course. But is it not wonderful? Yes: it was a clever trick to get those chains across the gulf, high up in the air: but not so clever a trick as to make a single stone of which those piers are built, or a single flower or leaf in those woods. The more you see of Madam How's masonry and carpentry, the clumsier man's work will look to you. But now we must get ready to give up our tickets, and go ashore, and settle ourselves in the train; and then we shall have plenty to see as we run home; more curious, to my mind, than any suspension bridge. And you promised to show me all the different rocks and soils as we went home, because it was so dark when we came from Reading. Very good. * * * * * Now we are settled in the train. And what do you want to know first? More about the new rocks being lower than the old ones, though they lie on the top of them. Well, look here, at this sketch. A boy piling up slates? What has that to do with it? I saw you in Ireland piling slates against a rock just in this way. And I thought to myself--"That is something like Madam How's work." How? Why, see. The old rock stands for the mountains of the Old World, like the Welsh mountains, or the Mendip Hills. The slates stand for the new rocks, which have been piled up against these, one over the other. But, you see, each slate is lower than the one before it, and slopes more; till the last slate which you are putting on is the lowest of all, though it overlies all. I see now. I see now. Then look at the sketch of the rocks between this and home. It is only a rough sketch, of course: but it will make you understand something more about the matter. Now. You see, the lump marked A. With twisted lines in it. That stands for the Mendip Hills to the west, which are made of old red sandstone, very much the same rock (to speak roughly) as the Kerry mountains. And why are the lines in it twisted? To show that the strata, the layers in it, are twisted, and set up at quite different angles from the limestone. But how was that done? By old earthquakes and changes which happened in old worlds, ages on ages since. Then the edges of the old red sandstone were eaten away by the sea--and some think by ice too, in some earlier age of ice; and then the limestone coral reef was laid down on them, "unconformably," as geologists say--just as you saw the new red sandstone laid down on the edges of the limestone; and so one world is built up on the edge of another world, out of its scraps and ruins. Then do you see B. With a notch in it? That means these limestone hills on the shoulder of the Mendips; and that notch is the gorge of the Avon which we have steamed through. And what is that black above it? That is the coal, a few miles off, marked C. And what is this D, which comes next?