Then, realizing that she might be plainly seen if anyone chanced to look her way, she began hastily to descend.

“He might come out of his igloo and see me,” she told herself.

That the thing the person had entered was an igloo she had no reason to doubt. Igloos go with kiaks and are built beneath the earth.

“But,” she said suddenly, “the other girls will know a great deal more about those things than I do. I must tell them at once. We will hold a council of war.”

CHAPTER XV
THE ISLAND’S SECRET

Twenty-four hours after Florence’s mysterious discovery, the cabin of the O Moo was pervaded by a quiet and studious atmosphere. Lucile, who was quite herself again, was mastering the contents of a book devoted to the study of the technique of short story writing. Florence was delving into the mysteries of the working of the human mind. Marian was doing a still life study in charcoal.

One might conclude that by some hosts of good fairies the yacht had been spirited back to its place on the dry dock. This was not, however, the case. The O Moo was still standing in the little stream on the sandy island. Its position had been altered a trifle. It had been poled out into midstream and there anchored. This precaution the girls had felt was necessary. In case the Negontisks attempted to board the yacht it would give those on board a slight advantage. It is difficult to board a yacht from kiaks.

That the strange persons who lived in holes beneath the sand dunes were these wild natives they did not doubt. “For,” Marian had reasoned, “who else in all the wide world would live in such a manner?”

“Yes, but,” Florence had argued, “how did they ever get to the shores of Lake Michigan anyway?”

The question could not be answered. The fact remained that there were people living beneath the ground on this island and that the girls were afraid of them, so much afraid that they were not willing, voluntarily, to expose themselves to view.