From Popular British Ballads, Ancient and Modern by Reginald Brimley Johnson, 1894:

THE LAKE OF COOLFIN

To the Lake of Coolfin the companions soon came,
And the first man they met was the keeper of game:—
"Turn back, Willy Leonard, return back again;
There is deep and false water in the Lake of Coolfin!"

Young Willy plunged in, and he swam the lake round;
He swam to an island—-'twas soft marshy ground:
"O, comrade, dear comrade, do not venture in;
There is deep and false water in the Lake of Coolfin!"

'Twas early that morning his sister arose;
And up to her mother's bed-chamber she goes:—
"O, I dreamed a sad dream about Willy last night;
He was dressed in a shroud—in a shroud of snow-white!"

'Twas early that morning his mother came there;
She was wringing her hands—she was tearing her hair.
O, woful the hour your dear Willy plunged in:—
There is deep and false water in the Lake of Coolfin!

And I saw a fair maid, standing fast by the shore;
Her face it was pale—she was weeping full sore;
In deep anguish she gazed where young Willy plunged in:—
Ah! there's deep and false water in the Lake of Coolfin!

Old Ballad. Recomposed by P. W. JOYCE.