upright and verified the other's words.

"They ran toward that opening among those trees. And I'll bet they
live in these caves up here behind us. I got a whiff of them as we
came past: they smelled like a zoo."

They had come out on top of the lava-flow, close to its end. The
molten rock had hardened to leave a drop of some forty feet to the
open glade below. Beyond that the jungle began, but behind them was
the lava bed, frozen in countless corrugations. Harkness rose and
helped Diane to her feet: they must force their aching muscles to take
up their task again.

He peered up the valley where a thousand fires smoked. "That stream,"
he said, "comes in from a little valley that branches off up there. We
had better follow it--and we had better get going before that gang
recovers from its surprise."

They were passing the first of the fires where the meat was smoking
when Chet called a halt. "Wait a bit," he begged: "let's take a
sirloin steak along--" He was haggling at a chunk of meat with a
broken flint when a spear whistled in and crashed upon the rocks.

* * * * *

Harkness saw the thrower. Beyond the lava's edge the jungle could be
seen, and from among the spectral trees had darted a wild figure whose
hairy arm had snapped the spear into the air.

There were more who followed. They were sliding down the slender
trunks that supported the branches and leafy roof high above the
ground. To Harkness the open doorway to the jungle seemed swarming
with monkey-men. The movement of the three fugitives had been taken as
a retreat, and the courage of the cave-dwellers had returned.

Harkness glanced quickly about to size up their situation. To go on
was certain death; if these creatures came up to meet them on the
lava-beds, the end was sure. The escarpment gave the three some slight
advantage of a higher position.

One vain wish for the pistol now resting in the deep grass beside a
vanished ship; then he sprang for the weapon that had been thrown--it
was better than nothing--and advanced cautiously to the lava's edge.

No concealment there; no broken rocks, other than pieces of flint; a
poor fortress, this, that they must defend! And the weapons of their
civilization were denied them.

Another spear hummed its shrill song, coming dangerously close. He saw
women-figures that came from the jungle with supplies of weapons.
Short spears, about six feet long, like the one he held. But th