surface of snow in front and found no tracks leading outward.

"They must be in here somewhere!" he exclaimed.

Pierre nodded his fur cap vigorously, and the two began a careful
examination of the underground place.

They found many little caves opening from the larger one, but no
trace of the boys. After a time a shout from Pierre drew Will to
his side. The fellow was peering into a crevice, in the rocky wall
which seemed to lead for some distance under the hill.

"Do you think they are hidden in there?" asked the boy.

Pierre explained in his barely understandable dialect that he
thought the boys might have escaped into the inner cavern and
started to make their way out in another direction.

"Then I'll go in after them," Will decided.

Before entering he called shrilly into the cavern, but only the
echoes came back to him. By considerable squeezing, he managed to
make his way through the opening. He then found himself in a
passage-like place, sloping upward. As he threw his light about
the interior, he heard a chuckle in the outer chamber where he had
left Pierre.

He turned in time to see the half-breed rolling great stones
against the mouth of the narrow opening by means of which he had
entered.