On the table before me sits the fossil imprint of a 45-million-year-old leaf that grew just north of where Scripps Ranch lies today. It was captured in a chunk of siltstone, which dusts my fingers with powdery tan grains every time I hold it. The fossil rock is heavy, solid, and as incomprehensible as God. I live with minutes and hours, weeks and months. Five thousand years of recorded history seems knowable vaguely. Forty-five million years is so far beyond comprehension that it makes me laugh. Yet here’s this leaf, that old, and so well preserved I can count the delicate tertiary threads branching off the secondary veins.
Fossilized whale bone at Chula Vista construction site
I watched a local paleontologist pry the leaf fossil out of a hillside just north of where Mercy Road runs east off I-15. He had already collected so many similar specimens from this site that he gave me this one. His gesture underscored what I have learned: that stupefyingly ancient objects come out of the ground here routinely, abundantly. Over the past 20 years, dozens of amateur and professional paleontologists have been drawn to local fossil beds that in some cases rank among the richest in the world.
Third floor, Natural History Museum
Those fossil beds are located, broadly speaking, in two areas: the Anza-Borrego Desert and the coastal zone. (Most of the local mountains contain no fossils because they’re made of granitic rock, formed from magma deep within the earth, where nothing lived.) The story of paleontology in San Diego is thus two stories, one being played out in the state park and the other in the city. Marvin and Aletha Patchen introduced me to the former. The Patchens have a comfortable home set among the cluster of desert dwellings known as Canebrake, a tiny community just outside the state park boundaries, about 20 miles northwest of Ocotillo. Their living room faces east, where in the distance, across highway S2, stretches a choppy sea of brown. That’s the Vallecito Badlands. “But we call them the Goodlands,” Aletha interjects. “They’re full of surprises.
Althea and Marvin Patchen. When George Miller died three years ago, the Patchens lost their status as collecting assistants.
Photo by Robert Burroughs
All the badland areas in the park tand there are seven) come as a surprise after driving through the terrain that adjoins them One minute you’re in an austere world of broad washes and massive bluffs, and then you reach a scene as busy as the facade of a Chur-rigueresque cathedral.A network of bony ridges splay out in all directions, and from them sag hillsides more folded and wrinkled than the oldest skin. Reflected sunlight turns the ndgetops a skeletal white, but the rest of the land is painted in tans and browns and, in the recesses, sepulchral black.
Tom Demere says San Diego's five dinosaurs must have either died on the beach or were carried offshore by a stream.
Looking down upon the badlands, visitors often compare them to moonscapes. But they’re even more otherworldly when observed from within. It’s there that you can see just how lifeless the maze-like passages arc. how thoroughly flood waters, winds, heat, and and-ness have stripped the rock of any plants or animals. The pathways may be confounding, but the well-scoured walls seem to conceal nothing. You'd pever know that, in Marvin’s words, they’re "a hotbed of bones.’’
Aletha says she can remember the precise moment when old bones first seized her imagination. It was about 1971, a few years before Marvin retired from a career publishing aviation magazines. The couple, who had just moved from Covina to Ramona, were used to hiking in Anza-Borrego’s badlands. and one day they set off into Arroyo Tapiado with an acquaintance who worked at the Los Angeles County Natural History Museum. This fellow pointed out some fossil scraps on the trail. He didn’t collect them because they lacked end joints or other identifiable features. But the Patchens asked a lot of questions, and on their subsequent desen hikes they started spotting what they had previously overlooked.
At first they didn’t touch any of the bones they chanced upon. Anyone who picks up a fossil in the state park without written permission risks a stiff fine. But the Patchens soon became friends with George Miller, the only person who held an official collecting permit at that time. A Canebrake resident. Miller had previously worked at the La Brea Tar Pits for the Los Angeles County Natural History Museum. Then he had gone on to teach paleontology classes for Imperial Valley College. The Patchens began alerting him to their discoveries and leading him back to sites that eventually became so numerous that Miller had to bring along his paleontology students to help with the collecting. After perhaps a year, “it finally got to a point where we were overwhelming him," Marvin says, so Miller applied to have the Patchens added to his permit as field assistants.
This freed them to collect and, if necessary, work on the fossils immediately. Sometimes liquid hardeners must be applied to protect fragile fossil bone from disintegrating, and Marvin estimates that fossils from the Vallecito Badlands require painstaking excavation perhaps 20 percent of the time. (Other times they can simply be picked up or lifted out in a chunk of dirt) The Patchens occasionally have had to hack steps out of rock with a pick in order to reach inaccessible pieces. At other times, they've hauled gunny sacks full of “matrix” — fossil-bearing dirt — back to their home, to be washed, screened, and sorted under a microscope or a big lens. “That’s a tedious job,” Aletha comments. “But it’s fun if you think you might find something.”
And indeed the couple found plenty over the years, hundreds of bones from a menagerie that included the familiar desert denizens: primeval rabbits, turtles and tortoises, lizards, rodents. The Patchens also unearthed surprises. On one occasion, they were hiking in a side canyon off Hueso Wash when a long, slender projectile sticking out of a cliffside caught Aleiha’s eye. Excavation proved it to be a deer antler, but not one that George Miller had ever seen before. Tentatively. Miller named it Navahoceros platiceros alethai, after Aletha, and he sent the specimen to an antler expert in Denmark, who finally concluded that it came from a species of deer previously unknown.
Other Patchen finds confirmed what was already pretty well established, namely, that at various times over the interval between one and five or six million years ago. the Vallecito Badlands looked like parts of East Africa. Lush trees and plants filled a grasslands that stretched as far as the eye could see. Overhead, giant vultures and other birds wheeled on gentle wind currents. The savannah resounded with the sounds of llamas, camels, horses, zebra and other large mammals. “We found the mandible [part of a jaw bone) of a peccary (a wild swine] that turned out to be the only one of its kind ever identified west of Nebraska” boasts Marvin. Once he and his wife found part of an ancient tapir — an animal whose present-day relatives only inhabit the tropical rain forests of Central and South America and who defecates exclusively in water.
To find these remains, “We were willing to spend hours of arduous, tedious hiking in places that most people wouldn’t even go," Marvin says. He speaks in the past tense because he and his wife aren’t actively collecting fossils at the moment. George Miller died three years ago. and the Patchens subsequently lost their status as collecting assistants. They hope to get permission to collect again someday, but in the meantime they continue to hike in the Vallecito Badlands and to scan their surroundings^keenly. One recent spring morning, they took me into one of the side canyons of Arroyo Seco del Diablo. We followed a course that Marvin still dubs “the loop hike,” even though recent rains built up a high earthen wall that blocks the circuit he once followed.
Rain waters regularly reshape and redecorate these serpentine passages. They tumble has ketball-sized chunks of sandstone into knobby “concretions” that litter the paths They wear away sand and mud layers from gullies studded with cobblestones, creating corridors with the coloration and form of gigantic peanut brittle. The flood waters coat certain overhangs with a thickly drippy texture that could be the work of a stucco contractor gone berserk; other wall surfaces bear delicate ripple marks. From a paleontological point of view,
“Rains do both good and bad," comments Marvin. “Sometimes they’ll take an exposed bone and tumble it or break it. Or they’ll cover something up which was exposed. Or uncover something which you couldn’t see before.”
Because there's so little vegetation, it’s easy to observe how much the earth has been crumpled and twisted in this part of the world. Fine striations in the hillsides stand out like contour lines on a map; these are the sedimentary layers out of which this rock was built when water flowed here and deposited sand, silt, and other material. But instead of being more or less horizontal, as the layers must have been originally, they now tilt at crazy angles and plunge into the ground or end abruptly at the blufftops. “You can’t follow any layer for long," Aletha complains. That really impedes paleontologists since the best way to find fossils is to search along geological layers in which something has already been discovered.
Massive forces within the earth caused all the tilting and jumbling. Even today the Anza-Borrego Desert Slate Park is a remarkably jumpy place. Both the Elsinore and the San Jacinto fault zones penetrate it, and the San Jac is considered to be the most active in California. Moreover, the San Andreas Fault lies just 35 miles to the east. Various measuring devices implanted throughout the park detect an average of 30 earthquakes per day, some 11,000 per year. Though most are “micro-quakes,” some of the temblors have been substantial, and any kind of movement adds up over the course of eons. All this seismic activity is one of the factors that distinguishes the San Diego County badlands from the famous formations in the Dakotas, where the earth has been considerably more stable. “There [in the Dakota badlands] they’ll find more fossils in a day than we’ll find in a year,” Marvin Patchen states. The Dakota badlands are also far more ancient — ranging from 30 to 40 million years old. In contrast, the oldest parts of the Anza- Borrego badlands were formed just 5 or 6 million years ago, at the end of the geological epoch known as the Miocene and the beginning of the Pliocene epoch. The newest sediments date back some 200,000 years, to the end of the Pleistocene epoch.
The relative youth of the park’s sediments doesn’t detract from their geological distinction, according to park ranger and paleontologist Paul Remeika. He says that nowhere else in North America was a thicker section of sediments deposited during the combined Plio-Pleistocene time span. That doesn’t mean you can drill down in any spot in the park and penetrate all those layers; they weren’t laid down one right on top of the other. Remeika instead suggests imagining a stack of 15 books that has been knocked sideways so that the volumes overlap or adjoin. The sedimentary layers in the park today resemble the sprawled stack. But if you measure them and add them up, they total some 15,000 feet thick. “That’s three times the thickness of the Grand Canyon,” Remeika exclaims. “And it’s fossiliferous throughout its entire exposure. We have the largest repository of [terrestrial] vertebrate and invertebrate fossil remains of that time in all of North America." Sediments from three major sources contributed fl to creating Anza-Borrego’s geological wonderland. Remeika says one was the Gulf of California, which at one point invaded the Salton 1 Trough and covered a large part of what is now the southeastern section of the park. Fossil remains of oysters, large predatory coned snails, corals. sand dollars, shark teeth, and other signs of marine life abound there. In their northern reaches, these sea sediments intermingle with sediments from the second major source: the ancestral Colorado River. Remeika says that that great waterway didn’t always follow its current pathway to the sea; the river’s main trunk probably worked its way back and forth over what is now the parkland, like a wiper moving over a car’s windshield. Sometime between three and four million years ago, either the river’s main trunk or various tributaries started draining across what is now the middle section of the park. Animals sometimes died and sank into the oozy mud of this delta. The flowing water brought in layers upon layers of additional silt and sand, and over time some of the buried bones underwent permineraliza-tion — the process in which minerals gradually replace organic content and literally turn what was once alive into stone.
Remeika says the third great source of sedimentation in the park was (and still is) “alluvial fan deposits" — that is, sand and rocks washed down by flooding from the nearby mountains into the basins. “The alluvial fan deposits began during the Ice Ages,” Remeika says. “You had more rainfall then [roughly two million years ago], and there was mountain-building taking place." By about 200,000 years ago. the mountains to the west of the park (the Lagunas and San Ysidros) had risen so high as to effectively block most of the moisture from crossing them. Plants and animals that had thrived for millenia died or moved away as the climate grew hotter and drier. Out of the rich sedimentary deposits, the forces of erosion started sculpting the badlands.
That process continues today, revealing fossils that tend to be older in the Vallecito Badlands. The animals whose bones were preserved in the Borrego Badlands (due east of Borrego Springs) lived recently enough to include the skeletons of prehistoric elephants — mammoths. Several of them have been excavated with the help of Betty Stout.
Stout is a short, 75-year-old, cigarette-smoking former housewife who first visited Borrego % Springs in the early ’60s. A fourth-generation Nevadan, she and her husband Chick raised their five children in Reno, where Chick was president of the Speidel newspaper chain. Jim Copley urged them to investigate Borrego Springs as a vacation site, and the Stouts eventually decided to build a winter home there. Shortly after the house’s completion (in 1969). Betty says she realized she would need new interests to help fill her lime in the desert. “So I went back to the University of Nevada to take courses in anthropology and geology — just to get a vague sort of overall understanding of the area "
“I’ve always been interested in anything of antiquity," she declares. “In school. I loved ancient history. I would rather have gone to Egypt or Greece w hen I was a little girl than Disneyland, had there been a Disneyland. Just looking down and seeing a shard of fossil bone is exciting to me."
Not long after moving to Borrego Springs. Stout met George Miller and persuaded him to teach a paleontology class in the town. That was almost 20 years ago. Ever since then, some kind of formal paleontology instruction has been offered in Borrego every fall and spring, and Betty Stout hasn’t missed a session. She says when Miller started, he could barely attract a required minimum of students, but now the class normally has a waiting list. Since veteran participants can enroll over and over and the class size is limited to 40, Stout says, “Sometimes we can’t even open up the registration to new members."
When Miller died. Stout went to Imperial Valley College and got the credential required for her to teach the class. She has shared the instructional duties with several other longtime participants. The classes no longer are held under the auspices of the college but instead have been sponsored by a group called the Natural History Association, “a very strong and very wealthy group” of park supporters, in Stout’s words.
It was the Natural History Association that back in the 1970s raised half the money to build the sleek Anza-Borrego Desert State Park Visitor’s Center. As originally designed, this facility included a paleontology laboratory, but the space became so popular as a lecture hall that the amateur paleontologists often couldn’t use it. They then shifted their work to a tiny building out toward Borrego Palm Canyon. One day Stout took her husband there to see the work being done on the lower jaw of a mammoth. The volunteer who was cleaning it was on her knees, sweating profusely in the cramped, sweltering quarters. Stout says her husband was so appalled by the working conditions that he immediately donated the money to build what is now known as the Stout Paleontology Laboratory.
Proudly. Betty leads the way into the lab. Workbenches holding dental picks, brushes, and other tools of the paleontologist’s trade line one wall; across from them are arrayed sand tables that cushion delicate fossils and absorb the din and sand scraped from them. All the preparation of the desen fossils takes place in this building, but these days the laboratory workers once again are seeing their space encroached upon — not by lecture audiences but by all the recovered fossils themselves.
Since this past spnng, 18 gray metal cabinets have taken over one quadrant of the room. The drawers hold some 6000 bones and teeth collected by Miller and his assistants over the years. Miller had always stored the collection in the Imperial Valley College Museum in El Centro. "It was basically an archeology museum," says Stout, who was among those who felt that the park's fossils never belonged there. The building was also so rickety that it was finally condemned. “In the next quake, it might have collapsed and we would have lost everything," Stout explains. This year the college finally acquiesced and gave up the collection. “Now they’re home again.” Stout says warmly.
Pieces too big to fit into the cabinets have been tucked into open shelves or wedged into crannies. Not all are bones. In a flat wooden tray, Paul Remeika has preserved a section of the very sandstone that caught his eye one morning back in 1981 .just five days after he first started working at the park. Accustomed to tracking animals, he stopped to examine the cloven hoofprints and realized immediately that they didn’t belong to any existing North American animal. Remeika knew roughly how old the rock was, and paleo-magnetic analysis pinpointed the age of the ridgetop at 3.08 million years. The camels that made the marks were one of eight different species that lived and died in the park, several of which left tracks. “Some of the tracks are eight and a half inches long; others are four inches long,” says Remeika. “Some are more elongated than others; some are more robust. We now have 12 sites yielding camel footprints within the park.” Together with the camel bones collected over the years, the tracks provide “a complete evolutionary lineage of the camel family here in Anza-Borrego.” the paleontologist declares.
If these three-million-year-old footprints are the most perverse items in the Stout Lab, they’re not the most dramatic. That distinction must be held by the curving mammoth tusk parked in back of the sand tables. Its two ends had to be removed for transport, but the central section still approaches 11 feet in length.
Stout says the mammoth’s' other tusk had been exposed to the elements for some time, and by the time it was discovered, “it had just turned to sawdust." The mammoth's skull, entombed in rock, fared better. Miller and his crew carefully “jacketed" it with paper, foam rubber, aluminum foil, and burlap soaked in plaster of Paris. The resulting package weighed close to 1500 pounds and had to be lugged over the nine-mile distance to the laboratory by a helicopter. Besides salvaging the tusk and cranium. Miller’s group also managed to recover most of the upper back vertebrae from the adult male, who ranks as one of the largest mammoths ever found in the Southwest. Stout sounds fonder, however, of what she calls “the little lady,” a female mammoth discovered by the group in the early 1980s. Varnished over the ages to a w arm shade of brown, her skull now resides in a display case in the visitors’ center. When the paleontologists first lifted this skull out of the ground, they found the shoulderblade and one or two other bones from a baby mammoth. “I think the baby got caught in quicksand and was crying for help." Stout says in a husky voice. “An then mama probably came trumpeting along, but she got caught too. And they died together."
Stout says the group has found so many mammoths that she's actually grown a bit tired of them. Instead she lusts for a saber-toothed cat.
“That to me would be the most exciting thing. They were the most wonderful animal!” Only a few small elements from saber-tooths have been found in the park. “He was too smart to get caught in any water or have a bad fall," she postulates. “He was too quick! That’s why we don’t find much of his remains."
Stout has other aspirations for the Anza-Borrego’s paleontological riches.
She’d like to see the Natural History Association fund a graduate student to live in the park and do research. Someday she’d like to see more of the park's fossils placed where the public could appreciate them. “I’d love to see the big mammoth replicated, for example. But that’s dreaming,” she says. ^ ome of the Anza-Borrego fossils did reach a wider audience last year, when the San Diego Natural History Museum borrowed them for an exhibition called "Unearthed.” From May 1 through November, the two strands of San Diego County paleontology interwove on the museum’s main display floor. Then the paleontology show had to yield up the space to the animatronic whales that succeeded them, and the desert fossils relurned to their home. The coastal fossils only had to travel one story up, to the third floor.
This space is now closed to the public, but when the museum was built in 1933, much of it was used for displays. Huge arched windows set just under the roof line admit light that reflects off the whitewashed walls and ceiling. Today the paleontology department shares one
section of this space with the museum's botanists. On the paleo side of the crowded quarters, six-foot-tall gray cabinets hog most of the central floor space, and open shelves jammed with big bones and fossils line the walls. Here Tom Demere has worked since 1979.
Demere says he really didn’t get interested in natural history until he took a geology course in college; he never was one of those children who live and breathe dinosaurs. Nor as a paleontologist has he ever been consumed by a desire to work with their fossils. That’s fortunate, because “Dinosaur people are bored to tears when they come here," he stales.
Dinosaur bones have surfaced only five times in San Diego County history. The first discovery occurred in 1967 and was made by a 13-year-old named Brad Riney. Riney had grown up in Clairemont and enjoyed looking for marine fossils in San Clemente Canyon and along local beaches. That day in 1967 he was keeping an eye open for fossilized nautilus shells along the sea cliffs next to the Marine Room in La Jolla. He noticed some nubs of bone protruding from an overhang and dug out an object that weighed perhaps five or six pounds. Paleontologists at L.A.’s natural history museum later identified it as part of a neck vertebra of a hadrosaur, a duck-billed dinosaur that lived 75 million years ago. They sent it back to Riney, who today recalls, “I practically slept with the thing!”
By 1981 the historic fossil was gathering dust in his garage when Riney got a call from Demere, asking if Riney would consider donating it to the museum. Riney agreed, met Demere, and not long after got a job helping with curatorial work in the paleo department. Since then Riney has gone on to find three more dinosaur remnants: a nearly complete hadrosaur thigh bone recovered in 1983 near the Carlsbad airport, a series of hadrosaur tail vertebrae unearthed in the winter of 1986 next to the Carlsbad Research Center, and in 1987 the nearly complete skeleton of a nodosaur, an armored herbivorous dinosaur that stood about 4 feet tall and 12 feet long. In 1988 a private citizen finally disrupted Riney's dino-bone monopoly by bringing in a Point Loma beach cobble containing part of a hadrosaur jaw. "And that’s it,” states Demere.
Demere says the reason San Diego doesn’t have more dinosaur fossils is "because we don’t have the rocks.” Dinosaurs roamed the earth from roughly 210 million to 65 million years ago, during the Triassic, Jurassic, and Cretaceous geological periods. Their bones are thus found exclusively in sedimentary rocks that were deposited during those periods and now lie exposed on the earth’s surface. But San Diego has no Triassic rocks, and only a few isolated patches of sedimentary Jurassic rocks have ever been identified here (in Penasquitos Canyon. Fairbanks Ranch, and a few other spots). These Jurassic rocks have been tilted and deformed fairly severely, according to Demere, and only a few fossils have emerged from it: tiny zooplankton, some remains of clams, squidlike mollusks. “Black Mountain is Jurassic but it’s mostly volcanic," Demere says, as is most of the other Jurassic rocks formed here. Bones that came in contact with molten lava would have been instantly incinerated.
San Diego does boast extensive Cretaceous rock formations, but Demere says the majority of the sedimentary Cretaceous all built up on the sea floor. “And there were no marine dinosaurs,” he declares. The remains of the five dinosaurs that lived in San Diego all came out of Cretaceous rock, but Demere says they must have either died on the beach or were carried offshore by a stream. “Either that or they were body-surfing,” he deadpans.
When he talks about which rock layers San Diego has and which it lacks. Demere hauls out that favorite paleontological analogy: books. He says the rock layers are like the chapters in the story of the earth — but there’s no single location where you can find them all preserved together. Coastal San Diego has several chapters, but some are incomplete. “For example, the Pliocene epoch worldwide represents the timespan from two to five million years ago. But we just have the uppermost part of it preserved here.” Only in the “little sliver of time” between two and three million years ago were sediments laid down to form the Pliocene rocks exposed in coastal San Diego today. Nonetheless, the presence of those “pages” and parts of other chapters makes San Diego one of the richest areas in the world for late Pliocene fossils, late Oligocene fossils, middle Eocene fossils, and late Cretaceous fossils, Demere asserts.
The 76-million-year-old Cretaceous rocks in which the dinosaurs were found make up the sea cliffs on both the west and east sides of Point Loma and also run through much of La Jolla. Demere says you find them in La Jolla Shores, starting at the beach and tennis club, and winding south through La Jolla Cove, around Windansea Beach, and continuing to Bird Rock. Some of the residents of the north side of Mt. Soledad have 76-million-year-old back yards, and this same rock formation is exposed in the road cuts around Palomar Airport in Carlsbad.
San Diego’s two- to three-million-year-old Pliocene rocks, like the Cretaceous, formed under the sea. Today they are exposed primarily in the South Bay, though they also rise up in the cliffs north of Crystal Pier in Pacific Beach, in those lining India Street, and in parts of Mt. Soledad. Three hundred feet thick, this layer “preserves remains of a whole variety of marine animals — from clams and snails, who lived on the sea floor, to the marine mammals, plus lots of sharks and bony fishes and even sea birds.” says Demure. “Because we have such a broad range of animals, (those rocks) preserve a fairly complete picture of what life was like in this part of the world at that time.”
Demere says Eocene rocks, ranging from 40 to 50 million years old. are exposed along both sides of Mission Valley. The gravel quarries there and at Daley Quarry in Murphy Canyon yield Eocene materials, which also form the sea cliffs from Scripps Institution north to Oceanside. Eocene deposits range eastward through the Santee Valley and extend north through Tierrasanta, Scripps Ranch, and the Poway Valley. "Rancho Bernardo is as far north is they go inland, and there are places in San Marcos where (Eocene] rocks are exposed, and parts of Vista. They also occur south of Mission Valley, but they’re not is well exposed."
Those Eocene rocks were deposited both on land and under the sea. Demere says.
“In fact, you can find the transition in some cases. San Diego has always been near the coast, and those rocks record both environments on land and environments offshore.
But the shoreline moved within that ten-million-year period. And in those times, the shoreline was more irregular. The look of our landscape was much different.”
While geologists mapped out the local Pliocene. Eocene, and Cretaceous rocks decades ago. another important geological “subchapter” only came to light recently. It involved the sedimentary rock beds lining the part of Chula Vista that points eastward like an arthritic finger. In 1986 the EastLake Development Company was about to begin grading the first phase of its 3000-acre project there, and Demere fully expected fossils to be exposed in the earth-moving operations. He assumed they would be Miocene fossils, since geologists had declared the EastLake rocks to be between 5 and 26 million years old. “The geologists had compared them to 15-million-year-old Miocene rocks in Baja California, just across the border,” Demere says. “They were similar." But when EastLake fossils began coming to light, the paleontologists who collected them very soon realized that the remains were not those of Miocene animals.
How could they tell? Demere explains that as paleontologists have collected fossils through rock layers from different millenia, the striking thing about those fossils is how they change through time. A clam will have 15 ribs in one layer, then 16 in another, then 30 in still younger layers. On a grosser scale, you’ll find trilobites in certain rocks, but then you get up to higher and younger rock layers and see no more trilobites. “You see the same sequences in similar layers of rocks," says Demere. “So you build up a standard.” Fossils that are no longer found in younger rock layers — because the animals became extinct — arc the so-called index fossils, the keys to conclusively identifying the relative age of any fauna.
Demere says that at EastLake the index fossils came from a tiny, plant-eating mammal called an oreodont. Another species of oreodont, about the size of a goat, also left its remains in the EastLake fossil grounds. But according to the paleontologist, it was the smaller animal that underwent the most rapid evolutionary change and lived on earth for a shorter stretch of time. Demers says confirmation of the revised estimate of the rock's antiquity came from EastLake’s rodent, dog, and camel fossils. “They compared with fossils from rocks that had been dated accurately in the mid-continent. And the rocks have historically been called late Oligocene,” that is, 26 to 30 million years old. Still more confirmation came just last year, when San Diego State University sent a sample of some of the Chula Vista rock to the U.S. Geological Survey in Denver. Using radiometric techniques on some of the volcanic material, the Denver geologists pinned down the date of the sample to 29 million years.
So far EastLake has yielded thousands of fossils representing far more species for that time period than any other site in California. Demere says that as a result, the South Bay Oligocene findings have become the statewide standard for understanding life 29 million years ago — at least on land (since only land animal fossils have emerged from EastLake's fine gray sandstone). Catlike carnivores about the size of mountain lions prowled the arid landscape. Dogs also hunted, as did foxlike animals and a big-headed extinct mammal known as a hyaenadon. Only pieces of the latter have surfaced, according to Demere, but from these we know that the Chula Vista hyaenadons were related ecologically. not evolutionarily, to hyenas. “They were just given that name because they could crush bones.”
Among EastLake’s plant-eaters, the two kinds of oreodonts appear to have been most numerous, but rhinoceroses, camels, and a kind of mouse deer also grazed in the area. Demere says that various rodents and squirrels lived among them, along with tortoises and lizards. “We’ve found a crane-like bird. And what appears to be the world’s oldest quail.”
Today that quail's skeleton resides in the wide flat drawer of one of the paleontology department’s metal cabinets. Demer6 pulled it out for me. Still half-embedded in a small block of sandstone, the skeleton has collapsed like a discarded marionette, so it’s hard to tell just what it was. Some of the bones are thin as toothpicks, and all of them glisten, as white as the teeth of a toddler.
Demere moved on to open drawer after drawer filled with the brown bones of small oreodonts. He pointed out balloon-shaped ear canals within the fragile skulls; the little fellows must have heard well. From another drawer, the paleontologist extracted vials containing rodent teeth so tiny that they're mounted on pin heads. We looked at rhino scraps and reptile fragments and at the femur of a three-million-year-old camel that once strolled near Otay Mesa and stood almost twice as tall as a man.
Some drawers also held little pink cards noting various specimens that are out on loan. Paleontologists in New York had borrowed a number of primate and rodent bones, for instance. A carnivore from another rock unit had been flown to Chicago. That’s how some of the most important dramas in paleontology unfold; when scientists delve into museum drawers such as these and draw new inferences from their contents. But getting them from the field into the drawers is no easy task.
“Collecting the fossils is the most straightforward part," Demere said with a sigh. "Preparing them and curating them takes more time." He’s the only permanent staff member in the paleontology department. A half dozen volunteers do help with the tedious tasks required to transform the fossils from curios into potential clues to the earth’s distant past. But unprepared specimens clutter the tops of many of the cabinets; on the day of my visit. Demere showed me some that had been brought in almost a year before.
They came from “Jeff*s Site.” a spot in Oceanside along Highway 78. Demere explained that back in the early ’80s, Jeff Dahlgren was an elementary school child who got interested in hunting for fossils near his grandmother's house. One day he took some of his specimens to the museum. “We have people bringing things in all the time. They find things in their back yards. As the winter rains wash the slopes, they erode and things are exposed. Usually they're nothing." In this case, however, the boy’s discoveries led to what Demere says has turned out to be the richest Eocene bone bed in the county. “God. it’s just full of fossils!”
Demere says he never discourages amateur fossil-hunters such as Jeff. It’s not illegal for American citizens to own fossils (the way it is in Canada and Mexico, where fossils are considered to be "national treasures”). Some places, such as state parks, fiercely prohibit collection, but many other areas are unrestricted. Mercenary fossil scavengers do take advantage of this. Demere notes with disgust. He says the Tucson Gem and Mineral Show is notorious for its wares; even dinosaur fossils command a price there. (German and Japanese industrialists have been the biggest buyers.) Most gem and mineral shops sell smaller fossils, as do some other shops such as the Collector jewelry store in La Jolla. Fossil sellers "have dollars in their eyes, and they don’t see the scientific and aesthetic values of these things," Demere states. But ordinary citizens who collect fossils fall into another category, in his view. “If [collecting] sparks their interest in the earth and changes their perception of time, that’s fine.” And it sometimes does lead to important scientific finds, like Jeff's site.
Demere says a similar incident occurred around 1984. when a San Diego State student brought in a shark’s tooth she had found while walking in a Mission Hills canyon. The paleontologist was so intrigued that he set out to discover how the fossil got to where the woman spotted it. He found an exposure of rock from the Pliocene San Diego formation; following it led him to a bone layer. “We collected hundreds of specimens over a period of about two months," he says.
The National Geographic Society paid for that dig. but outside funds don't arrive here often, and the San Diego Natural History Museum doesn't have much money for paleontological field work. Nonetheless, over the last ten years, more fossils have been dug out of the ground — by professional paleontologists who were paid for their labors — than at any other time in San Diego's history. For the most part, local developers have picked up the tab.
They've been obeying the California Environmental Quality Act. comprehensive legislation passed in the late ’70s that governs all aspects of the environment, including paleontological resources. Demure says that some local governments, such as the County of San Diego, simply ignore the paleontological requirements. But since 1980 most local cities have begun making developers put together programs for fossil collection. “That doesn’t mean all fossils,” explains Demere. “It means a representative sample of the materials" on the developers’ property. He says when developers first encounter the law, they usually fear that everything will stop whenever a bone is found. "But once they realize that doesn’t happen, then [the paleo work] becomes just another element in the project."
“It needs to be done, and we're willing to do it," says Ed Elliot, executive vice president of engineering for McMillin Communities. Elliot estimates that McMillin has probably spent more than $250,000 for paleo recovery work in Chula Vista alone, over the last four years. “It is another one of those things that adds to the cost of housing.” he says. “But when you hear Tom's (Demere’s) side of it, you understand the importance of these things. He’s kind of like a kid in a toy store.... Where else would he ever get the money to go and look down 30,40,50 feet? He’s getting a free look.” Demere himself did some of the contract paleontology work in the early '80s, moonlighting with a separate company that he called PaleoServices. These days he still owns it, but four other employees do most of the field work. Elliot from McMillin says that Demand also gets help from heavy equipment operators on the job sites. ‘Tom can really set the scene so you can visualize w hat could have happened to cause all these animals to get trapped. And he’s the type of guy that will go have a bag lunch w ith the guys and talk to them and in essence get eight or ten assistants.”
“They really get into it," concurs Demere. “It can be a pretty boring job to go around in circles all day. ‘Cause they think they're just moving dirt. But when they realize that these are the sediments of an ancient river or an ancient sea and that they have remains in them...it adds a new dimension to their job. Some of them, especially the bulldozer operators who are sitting up high and going slow, can actually spot things. And the material just speaks for itself. When you see a skull with teeth, and it’s beautifully preserved and intact, or when you see a whole body with legs and fingers, it’s kind of hard to dispute its importance."
On the day that I went out to observe contract paleontology in action, I never got close to any bulldozers. The McMillan Company had deployed a battalion of them to the site that will one day be Scripps Ranch North, but most of the time I only heard them growling in the distance. I could see where they had toiled at changing the dark wild land into the pallid firmament of suburbia. Most people never get to observe this transformation in progress; public roads don't go to where it happens when it happens, as insect-like, these machines chew into the earth’s green cover, bite into rock, shave off the hilltops, cover the canyon bottoms. By the time they finish, one sort of world has disappeared. Another will quickly seal the ground again, but in the interim there is much for Richard Cerutti to do.
When I met him, Cerutti wore shorts, a T-shirt, safety vest, and a red PaleoServ ices baseball cap. He’s now 50. but he was only 9 when he saw his first fossil. His father, a building contractor, brought him along to the site of a church being built above Mission Bay. and there Richard noticed some fossil invertebrates in a bank of earth. He took them home, but it wasn't until he was in high school and his family moved to Paradise Valley that he started searching for fossils in the Pliocene cliffs there. Later he staged one-man fossil salvage operations at big construction sites around the county; along Tecolote Canyon Road; in the South Bay along the road beds cut for Interstate 805. “A lot of times they had guards for the equipment, so I would run in one side, collect fossils, and run out the other.” Every now and then he would call the local natural history museum to see if anyone was interested in his findings, “But they had other things going." Cerutti recalls. “They were looking at fossils out of state.”
Other matters also occupied Cerutti. including work as a production artist for the Phillips Ramsey advertising agency. Then one day in 1979 he spotted a news story about the excavation of a local whale fossil by Demere, who had just joined the paleontology department. Cerutti contacted him and eventually donated his entire fossil collection to the museum. (It doubled the local institution’s holding of marine Pliocene specimens.) By the time Demere began looking for help with the contract paleontology work, Cerutti had left art for carpentry and was ready for yet another career change.
It was Cerutti who gave me the 45-million-year-old leaf fossil, along with an explanation of its origins. The plant grew in the flood plain of an enormous river system, perhaps ten miles wide. Its sediments today make up much of the county’s Eocene rock layer. Known as the Poway Fan. this sedimentary material holds clues to where the river came from. They take the form of cobblestones made from pink and purple rhyolite, an exotic volcanic rock not found anywhere else in San Diego County. “But similar rhyolites do occur east of the San Andreas Fault in Sonora. Mexico, as bedrock,” Cerutti says. Scientists now believe that Sonora (which today lies about 200 miles southeast of here) once roughly lined up with San Diego before we slipped away from it along the faultline; 45 million years ago. a river flowing through these Sonoran rhyolitic hills picked up chunks of rock, rounding them along the way, before reaching the sea at San Diego. Much later our backcountry mountains rose from the once-low-lying topography of the Eocene. “They’ve dated the cobbles with radiometric techniques, and the dates are very similar," Cerutti says. “Trace element analysis also matches them up too.”
Besides my leaf, the river buried large, rhinoceroslike animals called bronothercs and uintatheres. A small primate with huge eyes, called a tarsier, lived among them, as did reptiles, shrewlike animals, small rodents, even a type of marsupial. “This site is spectacular." Cerutti exulted up on the top of a ridge where he had been working for some days. “We’re getting complete stuff out of it that’s only been known before by a few isolated teeth.”
For an hour or two, I watched him and another PaleoServices employee work in the pale earth of the ridgetop The bulldozers had scraped it bare, and recent rains had packed it down, so we sat comfortably around a small depressed area. Every once in a while. Cerutti hefted his lightweight pick and slammed it into the side of the depression, loosening a block of earth that he cradled in his lap. He took a short, flat knife and inserted it into the block, methodically breaking off baseball-sized chunks. When he finished dismantling one block, he began on another. It struck me that this is one of society’s archetypal punishments; a day spent breaking up rocks. But Cerutti looked content, and every now and then he found something that made him cry out with pleasure.