-cliffs fronting upon the ocean, or westward in the
direction of the inland sea was a question which baffled me. Were
there many passes or only one? I had no way of knowing. I could but
trust to chance. It never occurred to me that Nobs had made the
crossing at least once, possibly a greater number of times, and that he
might lead me to the pass; and so it was with no idea of assistance
that I appealed to him as a man alone with a dumb brute so often does.

"Nobs," I said, "how the devil are we going to cross those cliffs?"

I do not say that he understood me, even though I realize that an
Airedale is a mighty intelligent dog; but I do swear that he seemed to
understand me, for he wheeled about, barking joyously and trotted off
toward the west; and when I didn't follow him, he ran back to me
barking furiously, and at last taking hold of the calf of my leg in an
effort to pull me along in the direction he wished me to go. Now, as
my legs were naked and Nobs' jaws are much more powerful than he
realizes, I gave in and followed him, for I knew that I might as well
go west as east, as far as any knowledge I had of the correct direction
went.

We followed the base of the cliffs for a considerable distance. The
ground was rolling and tree-dotted and covered with grazing animals,
alone, in pairs and in herds--a motley aggregation of the modern and
extinct herbivore of the world. A huge woolly mastodon stood swaying
to and fro in the shade of a giant fern--a mighty bull with enormous
upcurving tusks. Near him grazed an aurochs bull with a cow and a
calf, close beside a lone rhinoceros asleep in a dust-hole. Deer,
antelope, bison, horses, sheep, and goats were all in sight at the same
time, and at a little distance a great megatherium reared up on its
huge tail and massive hind feet to tear the leaves from a tall tree.
The forgotten past rubbed flanks with the present--while Tom Billings,
modern of the moderns, passed in the garb of pre-Glacial man, and
before him trotted a creature of a breed scarce sixty years old. Nobs
was a parvenu; but it failed to worry him.

As we neared the inland sea we saw more flying reptiles and several
great amphibians, but none of them attacked us. As we were topping a
rise in the middle of the afternoon, I saw something that brought me to
a sudden stop. Calling Nobs in a whisper, I cautioned him to silence
and kept him at heel while I threw myself flat and watched, from behind
a sh