The peat gradually displaced an early forest of giant oaks.  Their stems are still there, standing rooted in the older clay.  Where they once stood no trees now grow.  The whole face of the land has changed.  Some great change of climate must lie behind this vanishing of vast forests, this gradual growth of peat-covered moors.  A dry climate must have changed to one much damper; heat must have changed to cold, warm winds to chilly storms.  In the southern promontories, among red sandstone hills, still linger survivors of that more genial clime—­groves of arbutus that speak of Greece or Sicily; ferns, as at Killarney, found elsewhere only in the south, in Portugal, or the Canary Islands.

[Illustration:  Muckross Abbey, Killarney.]

On the southwestern horizon from Toppid Mountain, when the sky is clear after rain, you can trace the outline of the Curlew hills, our southern limit of view from Knocknarea.  Up to the foot of the hills spreads a level country of pastures dappled with lakes, broken into a thousand fantastic inlets by the wasting of the limestone rock.  The daisies are the stars in that green sky.  Just beyond the young stream of the Shannon, where it links Lough Garra to Lough Key, there is a lonely cromlech, whose tremendous crown was once upheld by five massive pillars.  There is a kindred wildness and mystery in the cromlech and the lonely hills.

Southward again of this, where the town of Lough Rea takes its name from the Gray Lake, stands a high hill crowned by a cromlech, with an encircling earthwork.  It marks a green ring of sacred ground alone upon the hill-top, shut off from all the world, and with the mysterious monument of piled stones in its centre; here, as always, one huge block upheld in the air by only lesser blocks.  The Gray Lake itself, under this strange sentry on the hill, was in long-passed ages a little Venice; houses built on piles lined its shores, set far enough out into the lake for safety, ever ready to ward off attack from the land.  This miniature Venice of Lough Rea is the type of a whole epoch of turbulent tribal war, when homes were everywhere clustered within the defence of the waters, with stores laid up to last the rigors of a siege.

The contrast between the insecurity and peril of the old lake dwellings and the present safety of the town, open on all sides, unguarded and free from fear, is very marked.  But not less complete is the contrast between the ancient hamlet, thus hidden for security amid the waters, and the great cromlech, looming black against the sky on the hill’s summit, exposed to the wildness of the winds, utterly unguarded, yet resting there in lonely serenity.