at Frock. “You see, Doctor, our best clue remains our only clue—the weapon, the claw. That is why I continue to search for its origin.”
Frock nodded slowly. “You mentioned DNA?”
Pendergast waved the computer printout. “The lab results have been inconclusive, to say the least.” He paused. “I can see no reason not to tell you that the test on the claw turned up DNA from various species of gecko, in addition to human chromosomes. Hence our assumption that the sample might be degraded.”
“Gecko, you say?” Frock murmured in mild surprise. “And it eats the hypothalamus ... how extraordinary. Tell me, how do you know?”
“We found traces of saliva and teeth marks.”
“Human teeth marks?”
“No one knows.”
“And the saliva?”
“Indeterminate.”
Frock’s head sank down on his chest. After a few minutes, he looked up.
“You continue to call the claw a weapon,” he said. “I assume, then, that you continue to believe the killer is human?”
Pendergast closed his briefcase. “I simply don’t see any other possibility. Do you think, Dr. Frock, an animal could decapitate a body with surgical precision, punch a hole in the skull and locate an internal organ the size of a walnut that only someone trained in human anatomy could recognize? And the killer’s ability to elude our searches of the subbasement has been impressive.”
[202] Frock’s head had sunk on his chest again. As the seconds ticked off into minutes, Pendergast remained motionless, watching.
Frock suddenly raised his head. “Mr. Pendergast,” he said, his voice booming. Margo jumped. “I’ve heard your theory. Would you care to hear mine?”
Pendergast nodded. “Of course.”
“Very well,” Frock replied. “Are you familiar with the Transvaal Shales?”
“I don’t believe so,” said Pendergast.
“The Transvaal Shales were discovered in 1945 by Alistair Van Vrouwenhoek, a paleontologist with South Africa’s Witwatersrand University. They were Cambrian, about six hundred million years old. And they were full of bizarre life forms the likes of which had never been seen before or since. Asymmetrical life forms, not showing even the bilateral symmetry of virtually all animal life on earth today. They occurred, coincidentally, at the time of the Cambrian mass extinction. Now most people, Mr. Pendergast, believe the Transvaal Shales represent a dead end of evolution: life experimenting with every conceivable form before settling down to the bilaterally symmetric form you see today.”
“But you do not hold such a view,” Pendergast said.
Frock cleared his throat. “Correct. A certain type of organism predominates in these shales. It had powerful fins and long suction pads and oversized crushing and tearing mouth parts. Those mouth parts could saw through rock, and the fins allowed it to move at twenty miles per hour through the water. No doubt it was a highly successful and quite savage predator. It was, I believe,
Pendergast blinked. “And?”
“I’ve run computer simulations of evolution [203] according to the new mathematical theory of fractal turbulence. The result? Every sixty to seventy million years or so, life starts getting very well adapted to its environment. Too well adapted, perhaps. There is a population explosion of the successful life forms. Then, suddenly, a new species appears out of the blue. It is almost always a predatory creature, a killing machine. It tears through the host population, killing, feeding, multiplying. Slowly at first, then ever faster.”
Frock gestured toward the sandstone fossil plaque on his desk. “Mr. Pendergast, let me show you something.” The agent stood up and moved forward.
“This is a set of tracks made by a creature that lived during the Upper Cretaceous,” Frock continued. “Right on the K-T boundary, to be exact. This is the only such fossil of its kind we’ve found; there is no other.”
“K-T?” asked Pendergast.
“Cretaceous-Tertiary. It’s the boundary that marks the mass extinction of the dinosaurs.”
Pendergast nodded, but still looked puzzled.
“There is a connection here that has so far gone unnoticed,” Frock continued. “The figurine of Mbwun, the claw impressions made by the killer, and these fossil tracks.”
Pendergast looked down. “Mbwun? The figurine that Dr. Cuthbert removed from the crates and put on display?”
Frock nodded.
“Hmm. How old are these prints?”
“Approximately sixty-five million years old. They came from a formation where the very last of the dinosaurs were found. Before the mass extinction, that is.”
There was another long silence.
“Ah. And the connection?.. .” asked Pendergast after a moment.
“I said that nothing in the anthropology collections matches the claw marks. But I did not say there were no
