"I'll know after I make tracings and run them through the computer lab at the university. Most ancient inscriptions are not nearly as definite and distinct as these. The symbols appear to have a well-defined structure. The main problem is that we have no other matching epigraphs anywhere else in the world to act as a guide. I'm treading in unknown waters until the computer can make a breakthrough."

"How you doin' up there?" Marquez shouted from the cleft below.

"All done for now," Pat answered. "Do you have a stationer's store in town?"

"Two of them."

"Good. I'll need to buy a ream of tracing paper and some transparent tape to make long sheets I can roll-" She fell silent as a faint rumble issued from the tunnel and the floor of the cubicle trembled beneath their feet.

"An earthquake?" Pat called down to Marquez.

"No," he replied through the hole. "My guess is an avalanche somewhere on the mountain. You and Dr. Ambrose go on about your business. I'll run topside and check it out."

Another tremor shook the chamber with a stronger intensity than the last one.

"Maybe we should go with you," Pat said apprehensively.

"The tunnel support timbers are old, and many are rotten," warned Marquez. "Excessive movement of the rock could cause them to collapse, produce a cave-in. It's safer if you two wait here."

"Don't be long," said Pat. "I feel a touch of claustrophobia coming on."

"Back in ten minutes," Marquez a.s.sured her.

As soon as Marquez's footsteps faded from the cleft below, Pat turned to Ambrose. "You didn't tell me your appraisal of the skull. Do you think it ancient or modern?"

Ambrose stared at the skull, a vague look in his eyes. "It would take a laboratory to determine if it was cut and polished by hand or with modern tools. The only fact we know for certain is that this room was not excavated and created by miners. There would have to be an account somewhere of such an extensive project. Marquez a.s.sures me that old Paradise Mine records and tunnel maps show nothing indicating a vertical shaft leading to an underground chamber in this particular location. So it must have been excavated prior to 1850."

"Or much later."

Ambrose shrugged his shoulders. "All mining operations were shut down in 1931. A major operation such as this could not have gone unnoticed since then. I'm reluctant to lay my reputation on the line, but I'll state without equivocation that I firmly believe this chamber and the skull are more than a thousand years old, probably much older."

"Perhaps early Indians were responsible," Pat persisted.

Ambrose shook his head. "Not possible. The early Americans built a number of complex stone structures, but an enterprise of this precise magnitude was beyond them. And then you have the inscriptions. Hardly the work of people without a written language."

"This does appear to have the hallmark of a high intelligence," she said softly, her fingertips lightly tracing the symbols in the granite.

With Ambrose at her side, Pat began copying the unusual symbols in a small notebook until she could account for a total of forty-two. Then she measured the depth of the engravings and the distance between the lines and the symbols. The more she examined the apparent wording, the more perplexed she became. There was a mysterious logic about the inscriptions that only a meticulous translation could solve. She was busily taking flash photos of the inscriptions and star symbols in the ceiling when Marquez climbed through the hole in the floor.

"Looks like we're going to be here for a while, folks," he announced. "An avalanche has covered the mine entrance."

"Oh, dear G.o.d," muttered Pat.

"Not to fret," Marquez said with a tight grin. "My wife has gone through this before. She'll be aware of our predicament and will have called for help. A rescue unit from town will soon be on its way with heavy equipment to dig us out."

"How long will we be trapped here?" asked Ambrose.

"Hard to say without knowing how much snow is blocking the shaft opening. Could be only a few hours. Might take as long as a day. But they'll work around the clock until they clear away the snow. You can bet on it."

A sense of relief settled over Pat. "Well, then, as long as your lights are still working, I suppose Dr. Ambrose and I can spend the time recording the inscriptions."

The words were barely out of her mouth when a tremendous rumble rose from somewhere deep beneath the chamber. Then the grinding sound of crashing timbers, followed by the deep growl of falling rock, reverberated from the tunnel. A violent rush of air roared through the cleft and into the chamber as they were all pitched headlong onto the rock floor.

Then the lights blinked out.

3

THE RUMBLE DEEP WITHIN the mountain echoed ominously from the hidden reaches of the tunnel and slowly faded away into a smothering silence, while unseen in the pitch blackness, dust disturbed by the concussion rolled through the tunnel, into the cleft, and up through the opening of the chamber like an invisible hand. Then came the sounds of coughing as the dust clogged noses and mouths, the grit quickly clinging to their teeth and tongues.

Ambrose was the first to gasp out coherent words. "What in G.o.d's name happened?"

"A cave-in," rasped Marquez. "The roof of the tunnel must have collapsed."

"Pat!" Ambrose shouted, feeling around in the darkness. "Are you hurt?"

"No," she managed between fits of coughing. "The breath was knocked out of me, but I'm all right."

He found her hand and helped her to her feet. "Here, take my handkerchief and hold it to your face."

Pat stood quite still as she fought to get a clean breath. "It felt as if the earth exploded beneath my feet."

"Why did the rock suddenly give way?" Ambrose asked Marquez, unable to see him.

"I don't know, but it sounded like a dynamite blast to me."

"Couldn't the aftershock of the avalanche have caused the tunnel to collapse?" asked Ambrose.

"I swear to G.o.d, it was dynamite," said Marquez. "I ought to know. I've used enough of it over the years to recognize the sound. I always use low particle-velocity dynamite to minimize ground shock. Someone set off a charge with concentrated powder in one of the tunnels beneath this one. A big one, judging from the shock."

"I thought the mine was abandoned."

"It was. Except for my wife and myself, no one has set foot in here for years."

"But how-"

"Not how, but why?" Marquez brushed by the anthropologist's legs as he crawled on all fours searching for his hard hat.

"Are you saying that someone purposely set off explosives to seal the mine?" Pat asked, bewildered.

"I'll d.a.m.n well find out if we get out of here." Marquez found his hat, set it over his dust-coated hair, and switched on the little light. "There, that's better."

The little light gave but token illumination inside the chamber. The settling dust had the eerie and forbidding look of a waterfront fog. They all looked like statues under the dust, their faces and clothing the color of the surrounding gray granite.

"I don't care for the way you said 'if.' "

"Depends on which side of the cleft the tunnel collapsed. Farther into the mine, we'll be clear. But if the roof fell somewhere between here and the exit shaft, we have a problem. I'll go and take a look."