heir
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
stone circle, which the first growth of peat found already there, must
be at least as old, and may be indefinitely older. By careful count it
is found that one foot of black peat is made up of eight hundred layers;
eight hundred summers and eight hundred winters went to the building of
it. One foot of black peat, therefore, will measure the time from before
the founding of Rome or the First Olympiad to the beginning of our era.
Another foot will bring us to the crowning of Charlemagne. Yet another,
to the death of Shakespeare and Cervantes. Since then, only a few inches
have been added. Here is a chronometer worthy of our great cromlechs and
stone circles.

Some of these, as we saw, rest on the clay, with a sea of peat twelve
feet deep around and above them. Every foot of the peat stands for eight
centuries. Since the peat began to form, eight or ten thousand years
have passed, and when that vast period began, the great monuments of
ston