"May I come too?" she demanded.

He flung aside the temptation to answer her in kind, merely assenting,
with an explanation of his design. When the lamp was in order he held
it close to the wall and conducted a systematic survey. The geological
fault which favored the construction of the tunnel seemed to diverge to
the left at the further end. The "face" of the rock exhibited the marks
of persistent labor. The stone had been hewn away by main force when
the dislocation of strata ceased to be helpful.

His knowledge was limited on the subject, yet Jenks believed that the
material here was a hard limestone rather than the external basalt.
Searching each inch with the feeble light, he paused once, with an
exclamation.

"What is it?" cried Iris.

"I cannot be certain," he said, doubtfully. "Would you mind holding the
lamp whilst I use a crowbar?"

In the stone was visible a thin vein, bluish white in color. He managed
to break off a fair-sized lump containing a well-defined specimen of
the foreign metal.

They hurried into the open air and examined the fragment with curious
eyes. The sailor picked it with his knife, and the substance in the
vein came off in laminated layers, small, brittle scales.

"Is it silver?" Iris was almost excited.