However the water was calm; not a ripple disturbed its surface.

Several times the settlers stopped on the bank, and observed it attentively.

Nothing appeared.
There was some mystery there.
The engineer was puzzled.
"Let us pursue this exploration to the end," said he.
Half an hour after they had all arrived at the southeast angle of the lake, on Prospect Heights.

At this point the examination of the banks of the lake was considered finished, and yet the engineer had not been able to discover how and where the waters were discharged.

"There is no doubt this overflow exists," he repeated, "and since it is not visible it must go through the granite cliff at the west!" "But what importance do you attach to knowing that, my dear Cyrus ?" asked Gideon Spilett.
"Considerable importance," replied the engineer; "for if it flows through the cliff there is probably some cavity, which it would be easy to render habitable after turning away the water." "But is it not possible, captain, that the water flows away at the bottom of the lake," said Herbert, "and that it reaches the sea by some subterranean passage ?" "That might be," replied the engineer, "and should it be so we shall be obliged to build our house ourselves, since nature has not done it for us." The colonists were about to begin to traverse the plateau to return to the Chimneys, when Top gave new signs of agitation.