circle of Stonehenge might be set, leaving a broad road all round it on
the grass.

From Fermanagh, where this huge circle is, we gain our best clue to the
age of all these monuments, everywhere so much like each other in their
massive form and dimensions, everywhere so like in their utter mystery.
Round the lakes of Erne there are wide expanses of peat, dug as fuel for
centuries, and in many places as much as twelve feet deep, on a bed of
clay, the waste of old glaciers. Though formed with incredible slowness,
this whole mass of peat has grown since some of the great stone
monuments were built; if we can tell the time thus taken for its growth
we know at least the nearer limit of the time that divides us from
their builders.

Like a tree, the peat has its time of growth and its time of rest.
Spring covers it with green, winter sees it brown and dead. Thus thin
layers are spread over it, a layer for a year, and it steadily gains in
thickness with the passing of the years. The deeper levels are buried
and pressed down, slowly growing firm and rigid, but still keeping the
marks of the layers that make them up. It is like a dry ocean gradually
submerging the land. Gathering round the great stone circles as they
stand on the clay, this black sea has risen slowly but surely, till at
last it has covered them with its dark waves, and they rest in the
quiet depths, with a green foam of spring freshness far above
their heads.

At Killee and Breagho, near Enniskillen, the peat has once more been cut
away, restoring some of these great stones to the light. If we count the
layers and measure the thickness of the peat, we can tell how many years
are represented by its growth. We can, therefore, tell that the great