“Neither. No single theory fits all the facts. I think it is all of the above, with the extinction set in motion by a cataclysm or series of cataclysms. Tsunamis. Volcanic eruptions that produced killing clouds and gas, altering the pattern of vegetation.”

“There's a hole in that theory too,” Arbatov said. “The evidence suggests that extinction occurred over a period of hundreds or thousands of years.”

“That wouldn't be a problem. My theory takes into account the discovery of vast numbers of mammoths found tumbled in a common grave, and explains why some of the creatures survived long after that. Evidence demonstrates that many were killed by sudden violence. But we also know that a few mammoth species were around when the Egyptians were building the Pyramids. The cataclysm weakened the mammoth herds to a point where disease and hunters could polish them off. The extinction of certain species had a ripple effect. The predators that preyed on the mammoths and other creatures would lose their food source.”

“I think you're onto something, but you're saying that this worldwide cataclysm occurred suddenly. One minute, the mammoths were peacefully chewing on grass. The next, they were on their way to extinction. Isn't that far-fetched?”

“Not at all. But I would be the first to admit that the theory of polar shift is controversial.”

“Polar shift?”

“A realignment of the poles.”

“None of us is a geologist,” Arbatov said. “Please explain.”

“I'd be glad to. There are two types of polar shift. A 'magnetic polar shift' would involve a reversal of the magnetic poles, causing all sorts of unpleasantness but nothing we couldn't survive. A 'geologic polar shift' would mean actual movement of the earth's crust over its molten core. Something like that could create a cataclysm like the one I believe killed the mammoths as a species.”

Arbatov was unconvinced. “You're basing your extinction theory on the theoretical shifting of the poles? You'll have to admit that it's unlikely that such a disruption could occur.”

“On the contrary. It has happened, and could happen again.”

Arbatov made a show of taking Karla's glass. “Our guest has had a little too much vodka.”

“I'll be glad to let you read my paper setting forth my theory, Dr. Arbatov. I think you'll find it enlightening. Especially the equations showing how a disruption in the electromagnetic field of the earth could precipitate a polar reversal.”

An argument broke out around the table between those who agreed with her theory and those who didn't. Despite their civilized veneer, it was evident that some tension remained among the group. She wasn't surprised. Scientists were no different from anyone else, except they were possibly more vain and petty. Maria's forcefully pleasant personality broke up the verbal brawl.

“My apologies for being so rude to a guest,” she said, shooting dagger eyes at her husband. “What are your plans for tomorrow?”

With Arbatov neutralized, the argument ended as quickly as it started.