The 6th Extinction (Sigma Force 10)

“If you move slowly, they shouldn’t bother us,” Harrington said. “They have no natural fear of people. As long as you don’t get too near one of their nests, we should be able to pass unscathed.”

“And if we do piss them off?” Gray asked.

“Avex cano have a flock mentality. They’ll attack en masse. See that hooked claw at the back of their legs. It’s used for gutting prey.”

“But mostly they’re docile,” Stella said. “Even friendly, sometimes curious.”

She demonstrated by stepping near one and holding out her hand. It hopped closer, cocking its head to one side, then the other. Only now did Jason notice it was eyeless. Small nostrils above a long paddle-shaped beak opened and closed.

She reached a little farther and ran her fingertips along the underside of that beak, earning a soft ululating noise from its throat. The sound spread to its neighbors, like a wave traveling outward from a pebble dropped into a pond.

Stepping forward, Stella followed those reverberations, easily passing through the flock, leading the way now. Jason was drawn in her wake, as much by the wonder of it all as his appreciation of the woman before him.

Nearby, an Avex stalked high-legged into one of the ponds, stirring up a phosphorescent wake in its passage, the glow rising from the thick jellylike growth floating atop the stagnant water. The creature scooped up a gullet full of that slime.

“They graze on those bacterial mats,” Stella said. “Very nutritious.”

“I’ll stick to a T-bone,” Kowalski commented, though he stared hungrily at the Avex flock as if trying to judge if they tasted like chicken.

The group passed unmolested, which perhaps is what made Jason let his guard down.

“Stop!” Harrington barked.

Jason froze. He had been about to step over a rock—only to have it sprout jointed legs, hard and chitinous, and scurry to the side. As it turned away, a curled tail came into view, tipped by a trio of six-inch-long stingers. From the glistening dampness to those spines, they must be venomous.

Harrington confirmed this by naming the scuttling creature. “Pedex fervens.”

Or roughly translated: hot foot.

Stella waved him onward.

He continued alongside Gray, but much of the momentary wonder from a moment ago had dried up.

After another long slog across the next hundred yards, the tunnel fell one last time and dumped into a massive space. The group gathered at the mouth of it. The sheer size boggled the senses.

“We call it the Coliseum,” Stella said.

That was an understatement.

The roof was beyond the reach of their meager pool of IR emitters. The walls to either side yawned ever wider, stretching like open arms into the distance. The river they had been following broke into thousands of small creeks, rivers, and streams, turning the place into a massive stony delta. Farther out, large lakes reflected their lamps, revealing the shadows of darker islands.

But closer at hand, the handful of petrified tree trunks that they had previously traveled past became a virtual stone forest ahead. The specimens found here dwarfed the largest redwoods, but instead of being merely trunks, the trees in this gargantuan cavern were perfect stone replicas, including intact branches and tinier stems, weaving an arched, leafless canopy overhead.

It was a fossilized sculpture of an ancient world.

Overhead, strange luminous creatures floated through those branches, possibly held aloft on some internal reservoir of hydrogen gas or helium. They looked like Japanese lanterns adrift on a breeze.

The group entered the vast space, necks craning at the sheer size. Jason had read about the discovery of a trench under the Western Antarctic ice, twice as deep as the Grand Canyon. This space could be its cavernous equivalent.

“Over this way,” Harrington urged.

The professor led them to the right, toward a wide shallow tributary of the delta. He splashed through the ankle-deep flow. Jason followed, but he had to fight the urge to tiptoe through the stream, still wary of the water. He watched for any new threat, while taking cues from Stella, who swept her IR beam ahead of her. He noted a double row of broken pillars, each as thick as Kowalski’s thigh, running alongside their path. At first he thought they were natural formations, but the rows were too uniform. Closer inspection revealed they were actually the stubs of wooden pylons, anchored by mold-blackened steel spikes.

The construction looked too old to be the handiwork of the British.

Stella noticed his attention. “They’re supports for a series of old bridges that fell apart long ago.”

“Who built them?”

Harrington called out, drawing them all forward. The answer—and their destination—lay ahead. It was parked askew, sitting on an isthmus of rock amid this dark delta. The huge vehicle’s bulk stood two stories tall, resting atop massive new tires. A handful of shiny ladders leaned against its side.

“We found it early on,” Stella said. “A team of British mechanics recently got her working again.”

Jason stared in awe.

It was Admiral Byrd’s old snow cruiser.

3:14 P.M.

Dylan Wright stood near the rear ramp of the largest CAAT. Irritated, he adjusted his body armor with one hand; with the other, he kept the long double barrels of his Howdah pistol balanced against his shoulder, prepared to challenge any threat found down here.

A smaller CAAT flanked his own, engines idling. The two vehicles’ headlamps shredded the darkness. On the roofs, Dylan’s teammates manned large LRAD units installed on top. One dish pointed forward, the other backward, ready to be deployed if necessary.

Dylan cursed under his breath as he stared up at the stalled gondola overhead. From its undercarriage, the remains of a ladder hung down.

So Harrington and the others had gone to ground—but where?

The growl of an engine drew his attention behind him. A second small CAAT came rumbling across the river atop its flotation treads, reached the nearby bank of rock, and climbed out of the water, demonstrating the craft’s amphibious nature.

It trundled up to Dylan’s vehicle and came to a stop. A window rolled down. His second-in-command poked his head out.

“The professor’s not holed up in that Kraut sub,” McKinnon said. “We checked it from stem to stern.”

Dylan had sent the Scotsman back to make sure Harrington hadn’t gone into hiding inside the German vessel.

Knowing this for sure now, Dylan faced forward.

Then they truly set off on foot.

Earlier, one of his scouts had found tracks along the riverbank, but Dylan had wanted to make certain someone hadn’t laid a false trail. He couldn’t believe Harrington had the bollocks for such an overland trek.