Langford turned back to the viewport. "When we see the lake we can look for another branching and the island. The island is right in the middle of the three rivers you saw in your vision. But it's just a dot on the electrograph. Are you sure it has a distinctive shape?" "It has a high, rocky shoreline," Joan assured him. "The central tributary cuts it in half and the other rivers flow around it. It's heavily forested, but the rent in the foliage where the ship came down is so wide you should be able to see it from ten thousand feet. The treetops are charred over a half mile radius." Langford smiled and squeezed her arm. "I bet you'd be happy mapping the Amazon in a bark canoe like a twentieth century explorer," he said. He grinned wryly. "A big rock island, mysterious as a cave of vampire bats, bisects the largest tributary west of the Tocantins, and it's just a dot on an electrograph to us. We've explored every crevice of every world in the System, but sometimes I envy our ancestors; they had elaborate pictorial maps to guide them." After a moment the ship leveled off, and the Great Cataract swept into view. It was a shining whiteness between two towering walls of foliage festooned with hanging vines, and flame-tongued flowers upon which the red sunlight seemed to dance. It foamed and cascaded over jagged rocks, swept around little clumps of submerged vegetation, and tore at sloping mud banks glimmering in the sunlight. Then the cataract became a receding blur and the wide river split up. Langford heard Joan cry out. * * * * * The island which loomed below was about eight miles in circumference and so heavily forested that it resembled a single shrub of wilderness proportions growing from a cyclopean stone flowerpot. Its high banks were almost vertical, its summit a charred mass of foliage cleft by an enormous rent which funneled the sunlight downward to a circular patch of bare, scorched earth. Something glittered on the forest floor, far below the blackened foliage. But whether it was the alien ship, or merely the glint of sunlight on the river which flowed completely through the island Langford could not determine from his aerial vantage point. A divided island was really two islands, but Langford was in no mood for geological hair-splitting. Erosion had failed to efface the original, hoary uniqueness of that towering mass of jungle, and for all practical purposes it was one island still, its high banks and far-flung aerial traceries hemming it in, and sealing its teeming life in eternal solitude. Langford turned and looked at Joan with eyes that were meshed in little wrinkles of confidence. "I'm going to gun her down through that gap!" he said. "We could crash through anywhere, but the best way to locate a wreck is to hew close to the cinder line!"