The island in the lake was probably a crannog, or artificial fortified
island, such as are common on the lakes of Ireland. Fundamentally the
story is an evident aetiological myth, intended to account for the
existence of some curious swampy hollow. In its present form it is
obviously suggested by Matt, xvii, 20. Note that VG does not seem to
contemplate the wholesale removal of the lake.
_Parallels_ are not wanting. Findian dried up a lake by prayer (CS,
192); and houses were shifted from the west side to the east side of
a flood for the convenience of Colum Cille (LL, 858). Saint Cainnech,
finding the excessive singing of birds on a certain island to be an
interruption to his devotions, compelled them to keep silence (CS,
376; VSH, i, 161).