After a long, long time though, the streams began to rejoin each other. Then low hills loomed through the thicker haze that filled the air here. The river flowed toward and through them. And here a wall of high mountains rose toward the sky, but their height could not be guessed. They vanished in the mist even before the cloud-bank swallowed them. The river flowed through a river-gate, a water-gap in the mountains. While day still held fully bright, the bobbing rafts went whirling through a narrow pass with sheer walls that rose beyond all seeing in the mist. Here there was even some white water. Above it, spanning a chasm five hundred feet across, a banded spider had flung its web. The rafts floated close enough to see the spider, a monster even of its kind, its belly swollen to a diameter of yards. It hung motionless in the center of the snare as the humans swept beneath it. Then the mountains drew back and the tribe was in a valley where, look as they might, there was no single tawny-red puffball from whose spreading range the tribesmen were refugees. The rafts grounded and they waded ashore while still the day held. And there was food here in plenty. But darkness fell before they could explore. As a matter of precaution Burl and his folk found a hiding-place in a mushroom-thicket and hid until morning. The night-sounds were wholly familiar to them. The noise of katydids was louder than usual--the feminine sound of that name gives no hint of the sonorous, deep-toned notes the enlarged creatures uttered--and that implied more vegetation as compared with straight fungoid flora. A great many fireflies glowed in the darkness shrouding the hiding-place, indicating that the huge snails they fed on were plentiful. The snails would make very suitable prey for the tribesmen also. But men were not yet established in their own minds as predators. They were, though, definitely no longer the furtive vermin they had been. They knew there were such things as weapons. They had killed ants for food and a pirate-wasp as an exercise in courage. To some degree they were acquiring Burl's own qualities. But they were still behind him--and he still had some way to go. The next day they explored their new territory with a boldness which would have been unthinkable a few weeks before. The new haven was a valley, spreading out to a second swamp at its lower end. They could not know it, but beyond the swamp lay the sea. Exploring, because of strictly practical purposes and not for the sake of knowledge, they found a great trap-door in the earth, sure sign of the lair of a spider. Burl considered that before many days the monster would have to be dealt with. But he did not yet know how it could be done.