Strata Blaster

The El Niño rains of a few days before, Rob Bronstein realized that February morning, had loosened the odd-looking rock from the hillside and sent it crashing to the edge of the old Mount Washington fire road, where his dog Keesha now sniffed it curiously.

Although the dog quickly dismissed the chunk of ocher-colored sandstone as neither threatening nor edible, Bronstein, a freelance artist, thought it worth a closer examination. The grayish, porous-looking bits protruding from the 200-pound lump looked to him like fossils, though of what he had no idea. Dr. Sam McLeod, a vertebrate paleontologist with the Los Angeles County Museum of Natural History, knew immediately what they were: cervical vertebrae and other bones of a 10-million-to-12-million-year-old baleen whale. Though whale fossils are not unknown in Los Angeles, this was the first ever discovered in Mount Washington. El Niño had delivered again. "Two things paleontologists wait for in Southern California," says McLeod’s colleague Dr. David Whistler, the museum’s curator of paleontology, "are El Niños and brushfires." Water, fire and, sometimes, wind "get the stuff out of the way so we can see the ground." Even then, McLeod says, finds like Bronstein’s are rare. "What the public might expect is that suddenly you get heavy rains and skeletons just pop out of the ground. That isn’t the way it happens. What it does do for the professional is give you a fresh surface to look at, that you can prospect for years." Whistler has done much of his fieldwork over the last 30 years at Red Rock Canyon State Park, where the southern Sierra merges into the hard expanse of the Mojave Desert, and there, too, El Niño has brought bounty. On Whistler’s first field trip of the season, late last month, he and his team of assistants and volunteers found a complete lower jaw of what he suspects is

Dinohippus leardi

, the largest fossil horse among Red Rock’s Miocene fauna. Like Bronstein’s whale, "This thing was just sitting there, lying on the surface." Between 7 million and 13 million years ago, while Bronstein’s whale and its ilk cruised the calm coastal waters from which Mount Washington and the rest of the Santa Monica Mountains had yet to emerge, Red Rock was dry land, its climate similar to the thorn scrub forests of today’s central Mexico. In the world before the mass extinctions of the last ice age, its terrestrial life was almost wantonly diverse. "The last time I counted there were 87 different animals known as fossils from Red Rock Canyon," says Whistler, ticking off a list of long-vanished species: ancient camels and rhinoceros, deerlike oreodonts, saber cats, bear-dogs, and on and on. Where now only one antelope species survives, half a dozen then flourished. Among the "little critters" in which Whistler himself specializes are squirrels, gophers, mice, lizards and snakes, some of whose fossil remains are best seen through a hand lens. But what paleontologists cannot see, they cannot study, which is why they rely on outside forces. Winds help, of course. Brushfires clear vast stretches of hillside chaparral every now and again. In urban regions, construction excavation in fossil-rich areas often yields remarkable finds. But for the sheer heavy lifting necessary to turn back a page of the geologic record, either in the Santa Monicas or in the desert, torrential rain is the tool of choice. Deserts, by definition, don’t get much precipitation. Even heavier than average rainfall will do little if parceled out over months of splishy-splashy daisy dampeners. Only the elemental ferocity of a canyon-scouring gully-washer-from-hell will do. The El Niño storms that hit Red Rock 15 years ago, cutting roads and killing two, certainly qualified. They also exposed large numbers of fossils, including the complete skull and forelimbs of a 9.75-million-year-old dog, a species so new it has yet to be named, which Whistler describes as "the finest carnivore skull ever collected from that particular rock formation." But even with 50 square miles of fossiliferous terrain to examine, pickings had gotten a bit thin until, early last September, an El Niño–bloated Pineapple Express unloaded 10 to 15 inches on Red Rock in just under four hours. "I’d been asking for this since 1983," Whistler admits. "It stripped as much as 3 or 4 inches off of virtually everything." It also wiped out the park headquarters. "The ranger keeps saying it’s all my fault," Whistler chuckles. "I said I didn’t ask for this much, but I’ll take what I can get. Actually, he’s excited we’re going to find more fossils." Both the Red Rock and Mount Washington finds are reminders, though, that, Hollywood and wishful thinking notwithstanding, complete fossil skeletons of any kind are extremely rare. For McLeod, therefore, paleontology is "an ongoing experiment. If I have this piece of an animal, then maybe someday I’ll find some more." In the meantime, of course, it never hurts to pray for rain.

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