them. One look at them would show you that no man's hand had put
them there. They look like a river of stone, if I may so speak; as
if some mighty flood had rolled them along down the valley, and
there left them behind as it sunk.

Now, whence did they come?

Many answers have been given to that question. It was supposed by
many learned men that they had been brought from the sandstone
mountains of Wales, like the rolled pebbles of which I spoke just
now. But the answer to that was, that these great stones are not
rolled: they are all squarish, more or less; their edges are often
sharp and fresh, instead of being polished almost into balls, as
they would have been in rolling two hundred miles along a sea-
bottom, before such a tremendous current as would have been needed
to carry them.

Then rose a very clever guess. They must have been carried by
icebergs, as much silt and stones (we know) has been carried, and
have dropped, like them, to the bottom, when the icebergs melted.

There is great reason in that; but we have cause now to be certain
that they did not come from Wales. That they are not pieces of a
rock older than the chalk, but much younger; that they were very
probably formed close to where they now lie.

Now--how do we know that?

If you are not tired with all this close reasoning, I will tell
you.--If you are, say so: but as I said at first, I want to show