"Can’t tell," Doc admitted. "But we’ll find out soon."

THEY went ahead hurriedly. Ham’s sword cane now came in doubly handy for slashing through the tangled growth. There were no forest lanes overhead — open stretches of branches through which Doc and Monk might have swung, anthropoidlike. They had to confine themselves to the earth.

Doc’s great bronze form came to an abrupt stop. Strange lights danced in his flaky golden eyes.

He was studying something he had found underfoot.

"What is it?" Long Tom inquired.

"Footprints."

"Let me see!" Oliver Wording Bittman hurried over.

Monk made an angry growl. "Kar?"

"No." A joyful brightness had lighted Doc’s golden eyes.

"What are you so tickled about?" Monk wanted to know.

"The footprints are Renny’s. I’d know those oversize tracks anywhere. Too, one of his shoes had a cut on the sole, and these tracks show just such a cut."

"Then Renny may be alive!"

They met Renny within the next few minutes. The elephant-like, big-fisted engineer had heard them. He came striding out of the tangled growth — the same as ever!

In one hand, Renny dangled the skin of a small, lemon-colored animal. In markings, this pelt resembled that of an undersized hyena.

"Here’s the history of my night!" Renny chuckled after greetings were exchanged.

Rapidly, he told of his wild ride on the great colossus with the three horns and the huge bony shield over its neck, of the playful thunder lizard in the lakelet, of his fight with the odorous and batlike flying reptile chick, and of the creature with the double row of upstanding, saw-teeth protuberance down its back.

He told of ducking into the handy trench, and of being buried. Then he came to the point where he shoved his person out into the hot night — and teeth had seized him.

Renny exhibited a small chewed spot on his shoulder. He shook the pelt of the hyenalike animal.

"It was this little thing bit me!" he laughed. "It made enough noise to be a lion. I choked the durn thing. I’m gonna make a pen wiper or somethin’ out of its hide to commemorate one of the worst scares I ever got. When it took hold of me, I sure thought the jig was up."

Doc suddenly remembered something. "That smoke! Did it come from a fire you made?"

"What smoke?" Renny asked vacantly. "I haven’t made any fire."

Chapter 19. ATTACK OF THE GNAWERS

"

IT’S Kar!" Ham muttered. "Kar made that fire!"

"Unless there are human beings residing in this place," Johnny pointed out.

"My thumb goes down on the idea that people may live in the crater," said Doc. "Thought that the comparatively defenseless human race could exist in here through the ages is a little preposterous. Anyway, we have seen no sign of monkeys or apes, which some evolutionists claim branched off from the same source stock as man."

"There’s not much doubt but that they did!" said Ham nastily, looking intently at Monk’s hairy, simian figure. "We have the living proof with us."

"A lot a shyster lawyer knows about evolution!" Monk grinned.

They set forth toward the fire again.

"Use caution!" Doc warned. "If it is only one of Kar’s men, we want to follow the chap to Kar. Or capture him alive and force him to tell us where Kar is!"

A stream of boiling-hot water barred their path. It was shallow, but too wide to leap across. They were forced to trail along it. But it only grew wider. It seemed to reach an indefinite distance. It was too hot for wading.

Doc solved the problem. Cutting two tough shoots not unlike bamboo, he fashioned a pair of makeshift stilts. The others quickly followed suit. With these, they negotiated the overly hot stream.

Oliver Wording Bittman, who wailed that he had never walked on stilts as a boy, was helped across the boiling water by Doc.

Soon after, the matlike jungle became horny with great upthrusts of rock.

At the very first of these stony juttings, Doc halted. He examined the rock with interest. He tapped at it quietly with his gun barrel. He borrowed Johnny’s glasses to use the magnifying lens on the left side.

"Hm-m-m!" he said thoughtfully.

If the bestial creodont which would have destroyed them except for the tobacco Doc threw in its eyes — if that animal was a mixture of many animals, so was this rock a mixture of many ores. Without proper apparatus for assaying, a great deal could not be told.

"What’s so interesting about that spotted dornick?" inquired Oliver Wording Bittman, fingering the scalpel on his watch chain.

"Just the wide variety of ores which it apparently contains," Doc replied.

Renny glanced at Doc. "You mean we may be near the region from which came the rare element or substance which is the basis of the Smoke of Eternity?"

"It’s a thought," Doc admitted.

GREATER was their caution now. The strange rocks became more plentiful. Indeed, the jungle gave way to a wilderness of glistening, mottled stone. This shimmering waste stretched directly before them until it ended against the sheer cliff of the crater side.

They penetrated farther. Signs of rare metals were all about. But it was doubtful if any were present in sizable paying quantities.

"I’d like to spend a month in here, just classifying rock types," declared Johnny, the geologist.

Doc Savage appraised the stony fastness.

"I want to look this over," he said. "I can move faster alone. You chaps wait here. The fire is on the other side. I’ll scout that, investigating this rock formation en route, then return."

His friends spread out among the strange rocks, inspecting curious formations. A couple of them sidled back into the jungle, intent on seeing if they couldn’t locate some kind of an edible herb. A meat diet would soon get monotonous, especially a meat with as strong a grassy taste as their primitive deer.

Doc continued into the rocks. They became difficult to get through, as though they were broken glass, the glass being as thick as a house.

This region of strange rocks was larger than he had thought. It must extend for at least two miles. It pressed against the cliff base its whole length.

In order to see the better, Doc clambered atop a vitrified mass.

Spang!

A bullet hit beside him. It sprayed wiry bits of lead into his bronze skin.

A quick leap put Doc in shelter. He was already in safety when the satanic laughter of the echoes came hopping across the arid rock wilderness.

The shot had come from the direction of his own friends!

Hardly more than a bronze blur in the steam-made twilight, Doc sped for his men.

He found them in excitement.

"Who fired that shot?" Doc demanded.

"None of us. It came from the jungle — to the right."

"Where’s Bittman?"

Oliver Wording Bittman was not about!

Doc sprang away. Herculean sinews carried his bronze form over knife-edged boulders and ridges around which it took the others minutes to go.

He topped a huge stone block.

Directly below him sprawled Bittman. The taxidermist’s body, so thin it was a skeleton and a few hard muscles, lay grotesquely atwist.

It was motionless!

A SAILING spring put Doc beside Bittman. His mighty bronze hands started to explore.

Spang!

Another shot!

The bullet would have slain Doc — if he had been one iota less quick on co-ordinating eye and muscles. For he had seen a rifle barrel stir out of the jungle foliage. He had flattened his giant form.

The rifle slug slicked through the space his body had vacated. It hit a rock and climbed away with a loud squawk.

Doc’s own gun rapped. Once! Twice!