is is the strangest!" he cried.
"What does it mean, old man?"

"I don't exactly know," answered Serge: "but I rather think it is a moss
blanket. Anyhow, that's an elegant place to crawl into out of the cold.
Seems to be plenty of wood too."

Serge was right in his conjecture. What appeared to be the river-bank
was merely a curtain of tough, closely compacted Alaskan moss, closely
resembling peat in its structure, one foot thick, and reaching from the
crest of an overhanging bank to the edge of the river. It had thus held
together, and fallen to its present position when the river undermined
and swept away the earth from beneath it. That it presented a sloping
surface instead of hanging perpendicular was owing to a great number of
timbers, the ends of which projected from the excavated bank behind it.
Serge had broken through the moss curtain, fallen between these timbers
to the beach, and then cut his way out. Now, as he suggested, what
better camping-place could they ask than the warm, dry, moss-enclosed
space from which he had just emerged.

"I never saw nor heard of anything so particularly and awfully jolly in
all my life," pronounced Phil, after the three travellers had entered
this unique cavern, and started a fire by which they were enabled to see
something of its strange interior. "And, I say, Serge, what a thoughtful
scheme it was on your part to provide a chimney for the fire before you
lighted it! See how the smoke draws up? If it wasn't for that hole in
the roof I am afraid we should be driven out of here in short order.
But, hello, old man! Whew--w! what are you throwing bones on the fire
for? It reminds me of your brimstone-and-feather experiment on Oonimak."

"Bones!" repeated Serge in surprise. "Are those bones? I thought they
were dry sticks."

"I should say they were bones!" cried Phil, snatching a couple of the
offending objects from the fire. "And, sure as I live, this log I am
sitting on is a bone too. Why, it's bigger than I am. It begins to look
as though this place were some sort of a tomb. But there's plenty of
wood. Let's throw on some more and light up."

"Toughest wood to cut I ever see," growled Jalap Coombs, who was hacking
away at another half-buried log. "'Pears to be brittle, though, and
splits easy," he added, dodging a sliver that broke off and flew by his
head.

"Hold on!" cried Phil, picking up the sliver. "You'll ruin the axe.
That's another bone you're chopping. This place