From the air, Thorvald's course would have been a crooked one, for he wove back and forth between the scattered islands of the chain, using their lee calm for the protection of the canoe. About two thirds of the group were barren rock, inhabited only by clak-claks and creatures closer to true Terran birds in that they wore a body plumage which resembled feathers, though their heads were naked and leathery. And, Shann noted, the clak-claks and the birds did not roost on the same islands, each choosing their own particular home while the other species did not invade that territory. The first large-sized island they approached was crowned by trees, but it had no beach, no approach from sea level. Perhaps it might be possible to climb to the top of the cliff walls. But Thorvald did not suggest that they try it, heading on toward the next large outcrop of land and rock. Here white lace patterned in a ring well out from the shore to mark a circle of reefs. They nosed their way patiently around the outer circumference of that threatening barrier, hunting the entrance to the lagoon. Within, there were at least two beaches with climbable ascents to the upper reaches inland. Though Shann noted that the vegetation showing was certainly not luxuriant, the few trees within their range of vision being pallid growths, rather like those they had sighted on the fringe of the desert. Leather-headed flyers wheeled out over their canoe, coasting on outspread wings to peer down at the Terran invaders in a manner which suggested intelligent curiosity. A full flock gathered to escort them as they continued along the outer line of the reef. Thorvald impatiently dug his paddle deeper. They had explored more than half of the reef now without chancing on an entrance channel. "Regular fence," Shann commented. One could begin to believe that the barrier had been deliberately reared to frustrate visitors. Hot sunshine, reflected back from the surface of the waves, burned their exposed skin, so they dared not discard their ragged clothing. And the wolverines were growing increasingly restless. Shann did not know how much longer the animals would consent to their position as passengers without raising active protest. "How about trying the next one?" he asked, knowing at the same time his companion was not in any mood to accept such a suggestion with good will. The officer made no reply, but continued to use his steer paddle in a fashion which spelled out his stubborn determination to find a passage. This was a personal thing now, between Ragnar Thorvald of the Terran Survey and a wall of rock, and the man's will was as strongly rooted as those water-washed stones.