Two hundred paces farther they arrived at the cutting, through which, as Pencroft had guessed, ran a stream of water, whether fresh or not was to be ascertained.  At this place the wall appeared to have been separated by some violent subterranean force.  At its base was hollowed out a little creek, the farthest part of which formed a tolerably sharp angle.  The watercourse at that part measured one hundred feet in breadth, and its two banks on each side were scarcely twenty feet high.  The river became strong almost directly between the two walls of granite, which began to sink above the mouth; it then suddenly turned and disappeared beneath a wood of stunted trees half a mile off.

“Here is the water, and yonder is the wood we require!” said Pencroft.  “Well, Herbert, now we only want the house.”

The water of the river was limpid.  The sailor ascertained that at this time—­that is to say, at low tide, when the rising floods did not reach it —­it was sweet.  This important point established, Herbert looked for some cavity which would serve them as a retreat, but in vain; everywhere the wall appeared smooth, plain, and perpendicular.

However, at the mouth of the watercourse and above the reach of the high tide, the convulsions of nature had formed, not a grotto, but a pile of enormous rocks, such as are often met with in granite countries and which bear the name of “Chimneys.”

Pencroft and Herbert penetrated quite far in among the rocks, by sandy passages in which light was not wanting, for it entered through the openings which were left between the blocks, of which some were only sustained by a miracle of equilibrium; but with the light came also air—­a regular corridor-gale—­and with the wind the sharp cold from the exterior.  However, the sailor thought that by stopping-up some of the openings with a mixture of stones and sand, the Chimneys could be rendered habitable.  Their geometrical plan represented the typographical sign “&,” which signifies “et cetera” abridged, but by isolating the upper mouth of the sign, through which the south and west winds blew so strongly, they could succeed in making the lower part of use.

“Here’s our work,” said Pencroft, “and if we ever see Captain Harding again, he will know how to make something of this labyrinth.”

“We shall see him again, Pencroft,” cried Herbert, “and when be returns he must find a tolerable dwelling here.  It will be so, if we can make a fireplace in the left passage and keep an opening for the smoke.”

“So we can, my boy,” replied the sailor, “and these Chimneys will serve our turn.  Let us set to work, but first come and get a store of fuel.  I think some branches will be very useful in stopping up these openings, through which the wind shrieks like so many fiends.”

Herbert and Pencroft left the Chimneys, and, turning the angle, they began to climb the left bank of the river.  The current here was quite rapid, and drifted down some dead wood.  The rising tide—­and it could already be perceived—­must drive it back with force to a considerable distance.  The sailor then thought that they could utilize this ebb and flow for the transport of heavy objects.