Between Galway Bay and the wide estuary of the Shannon spread the moorlands of Clare, bleak under Atlantic gales, with never a tree for miles inward from the sea.  Like a watch-tower above the moorlands stand.  Slieve Callan, the crown of the mountain abruptly shorn.  Under the shoulder of the great hill, with the rolling moorlands all about it, stands a solitary cromlech; formed of huge flat stones, it was at first a roomy chamber shut in on all four sides, and roofed by a single enormous block; the ends have fallen, so that it is now an open tunnel formed of three huge stones.

The coast runs southward from the Shannon to the strand of Tralee, the frontier of the southern mountain world, where four ranges of red sandstone thrust themselves forth towards the ocean, with long fiords running inland between them.  On a summit of the first of these red ranges, Caherconree above Tralee strand, there is a stone circle, massive, gigantic, dwelling in utter solitude.

We have recorded a few only out of many of these great stone monuments strewn along our Atlantic coast, whether on moor or cliff or remote mountain-top.

There are others as notable everywhere in the central plain, the limestone world of lakes and rivers.  On a green hill-crest overlooking the network of inlets of Upper Erne there is a circle greater than any we have recorded.  The stones are very massive, some of them twice the height of a tall man.  To one who stands within the ring these huge blocks of stone shut out the world; they loom large against the sky, full of unspoken secrets like the Sphinx.  Within this mighty ring the 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.