For a moment they all sat spellbound, mystified.

Then, as if seized by a sudden thought, Brownie hurried to the edge of the little island, exploring with his hands.

He lifted up some grassy soil that drooped and hung in the water, and tore it away.

As he did so there was revealed a ridge of heavy wood over which it had hung.

By the same process he exposed a yard or two of this black mud-covered edge.
"Well--I'll--be--_jiggered_!" said Billy.
"It's a scow or something!" said Brownie, almost too astonished to speak.
"The island seems to overlap it sort of like a pie-crust," drawled Townsend.
"The scow is the undercrust!" shouted Pee-wee, delighted with this comparison to his favorite edible.