"Bravely spoke, my lad; so we will, my hearty!" And we crawled and
clambered along till we came to the end of the point where it's all
stones and seaweed and big surf sometimes. The surf was not very
high this time,--just waves that went _whoosh_ and then pulled the
pebbles back with a nice scrawpy sound. The schooner was half-way
down to the Headland, not paying any attention to us.

"Ah ha!" Jerry said, "safe once more from an ignominious death. But,
Chris, look at the Sea Monster! What's happened to it?"

The Sea Monster is a bare black rock-island off the end of
Wecanicut. We called it that because it looks like one, and it
hasn't any other name that we know of. We'd always wanted awfully to
go out there and explore it, but the only time we ever asked old
Captain Moss, who has boats for hire, he said, "Thunderin' bad
landin'. Nothin' to see there but a clutter o' gulls' nests," and
went on painting the _Jolly Nancy_, which is his nicest boat.

But the thing that Jerry was pointing out now was very queer indeed.
It was just a little too far away to see clearly what had happened,
but it seemed as if a piece of rock had fallen away on the side
toward us, leaving a jaggedy opening as black as a hat and high
enough for a person to stand upright in.

"The entrance to a subaground tunnel!" Greg shouted, leaping up and
down in the edge of a wave.

He _will_ say "subaground," and it really is quite as sensible as
some words.