First. They were used to build Druid temples.

If you go to the further lodge of Dogmersfield Park, which opens
close to the Barley-mow Inn, you will see there several of them,
about five feet high each, set up on end. They run in a line
through the plantation past the lodge, along the park palings; one
or two are in an adjoining field. They are the remains of a double
line; an avenue of stones, which has formed part of an ancient
British temple.

I know no more than that: of that I am certain.

But if you go to the Chalk Downs of Wiltshire, you see these temples
in their true grandeur. You have all heard of Stonehenge on
Salisbury Plain. Some of you may have heard of the great Druid
temple at Abury in Wilts, which, were it not all but destroyed,
would be even grander than Stonehenge. These are made of this same
sugar-sandstone.

But where did the sandstone come from? You may say, it "grew" of
itself in our sands and gravels; but it certainly did not "grow" on
the top of a bare chalk down. The Druids must have brought the
stones thither, then, from neighbouring gravel-pits. They brought
them, no doubt: but not from gravel-pits. The stones are found
loose on the downs on the top of the bare chalk, in places where
they plainly have not been put by man.

For instance, near Marlborough is a long valley in the chalk, which,
for perhaps half a mile, is full of huge blocks of this sandstone,
lying about on the turf. The "gray wethers" the shepherds call