Is that why the place is called Bath?

Of course.  But the Old Romans called the place Aquae Solis—­the waters of the sun; and curious old Roman remains are found here, which we have not time to stop and see.

Now look out at the pretty clear limestone stream running to meet us below, and the great limestone hills closing over us above.  How do you think we shall get out from among them?

Shall we go over their tops?

No.  That would be too steep a climb, for even such a great engine as this.

Then there is a crack which we can get through?

Look and see.

Why, we are coming to a regular wall of hill, and—­

And going right through it in the dark.  We are in the Box Tunnel.

* * * * *

There is the light again:  and now I suppose you will find your tongue.

How long it seemed before we came out!

Yes, because you were waiting and watching, with nothing to look at:  but the tunnel is only a mile and a quarter long after all, I believe.  If you had been looking at fields and hedgerows all the while, you would have thought no time at all had passed.

What curious sandy rocks on each side of the cutting, in lines and layers.

Those are the freestone still:  and full of fossils they are.  But do you see that they dip away from us?  Remember that.  All the rocks are sloping eastward, the way we are going; and each new rock or soil we come to lies on the top of the one before it.  Now we shall run down hill for many a mile, down the back of the oolites, past pretty Chippenham, and Wootton-Bassett, towards Swindon spire.  Look at the country, child; and thank God for this fair English land, in which your lot is cast.

What beautiful green fields; and such huge elm trees; and orchards; and flowers in the cottage gardens!

Ay, and what crops, too:  what wheat and beans, turnips and mangold.  All this land is very rich and easily worked; and hereabouts is some of the best farming in England.  The Agricultural College at Cirencester, of which you have so often heard, lies thereaway, a few miles to our left; and there lads go to learn to farm as no men in the world, save English and Scotch, know how to farm.

But what rock are we on now?

On rock that is much softer than that on the other side of the oolite hills:  much softer, because it is much newer.  We have got off the oolites on to what is called the Oxford clay; and then, I believe, on to the Coral rag, and on that again lies what we are coming to now.  Do you see the red sand in that field?

Then that is the lowest layer of a fresh world, so to speak; a world still younger than the oolites—­the chalk world.

But that is not chalk, or anything like it.

No, that is what is called Greensand.

But it is not green, it is red.

I know:  but years ago it got the name from one green vein in it, in which the “Coprolites,” as you learnt to call them at Cambridge, are found; and that, and a little layer of blue clay, called gault, between the upper Greensand and lower Greensand, runs along everywhere at the foot of the chalk hills.