Even as he stepped aside from that weak second throw Carson drew back his right arm and let fly with the rock that was still in his hand. If missiles, he thought with elation, can cross the barrier, then two can play at the game of throwing them.
He couldn’t miss a three-foot sphere at only four-yard range, and he didn’t miss. The rock whizzed straight, and with a speed several times that of the missiles the Roller had thrown. It hit dead centre, but hit flat instead of point first. But it hit with a resounding thump, and obviously hurt. The Roller had been reaching for another rock, but changed its mind and got out of there instead. By the time Carson could pick up and throw another rock, the Roller was forty yards back from the barrier and going strong.
His second throw missed by feet, and his third throw was short. The Roller was out of range of any missile heavy enough to be damaging.
Carson grinned. That round had been his.
He stopped grinning as he bent over to examine the calf of his leg. A jagged edge of the stone had made a cut several inches long. It was bleeding pretty freely, but he didn’t think it had gone deep enough to hit an artery. If it stopped bleeding of its own accord, well and good. If not, he was in for trouble.
Finding out one thing, though, took precedence over that cut: the nature of the barrier.
He went forward to it again, this time groping with his hands before him. Holding one hand against it, he tossed a handful of sand at it with the other hand. The sand went right through; his hand didn’t.
Organic matter versus inorganic? No, because the dead lizard had gone through it, and a lizard, alive or dead, was certainly organic. Plant life? He broke off a twig and poked it at the barrier. The twig went through, with no resistance, but when his fingers gripping the twig came to the barrier, they were stopped.
He couldn’t get through it, nor could the Roller. But rocks and sand and a dead lizard… How about a live lizard?
He went hunting under bushes until he found one, and caught it. He tossed it against the barrier and it bounced back and scurried away across the blue sand.