To his surprise he found that the three dogs had stopped near a large tree, and were barking furiously at nothing.

But as soon as they saw him approaching they started off again, making the woods resound with their baying.

Having run about a quarter of a mile, he could perceive that again they had stopped.

When Crockett reached them there was no game in sight.

The dogs, barking furiously again, as soon as they saw him approaching plunged into the thicket.
For a third time, and a fourth time, this was repeated.