curious Perte de Lesse, swerves suddenly from its obvious course,
down the bright and cheerful valley, to plunge noisily through a
narrow slit in the rock--

"Where Alph, the sacred river, ran
Through caverns measureless to man
Down to a sunless sea."

Rochefort, which itself has a considerable cave, is a pleasant
centre for the exploration of these subterranean marvels.
Altogether this limestone region of the Ardennes, though certainly
not remarkable for mountain or forest splendour, comes as a
somewhat welcome relief after the interminable levels and
chessboard fields of East and West Flanders, or of the provinces
of Limburgh and Antwerp.