Thence it stretched away up the river for a hundred yards or more.

Now the only entrance big enough to admit a person into the root fortress was on the side next to the drift, and it opened only into an alley-way which the boys had partly found and partly made through the drift.

This alley-way led past several little aisles running out to the right and left for a dozen yards or so,--aisles formed by the irregular piling of the logs on top of each other.

In the fortress there were a dozen places at least, where the big roots were sufficiently wide apart to admit a grown man easily, but the boys had left the smaller roots which covered these gaps undisturbed, and cut only the one entrance.

After cutting that on the side next the hammock, they had moved some of the drift so as to close up the sides of the entrance and make it open only into the alley-way.