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PALEONEWS: Del Puerto Canyon
forwarded from sci.bio.paleontology
-------- Original Message --------
Subject: Del Puerto Canyon
Date: Thu, 08 Jun 2000 15:21:51 GMT
From: Inyo <email@example.com>
Here's an article I ran across over the newswires, a story all about
the man who first reported to science dinosaur remains from California--
they came from Del Puerto Canyon in Stanislaus County. Though the
article does not mention the specific geologic rock unit the dinosaur
skeletal elements came from, the bones had weathered out of the Upper
Cretaceous Moreno Formation, a locally fossil-rich accumulation of dark
gray to to dark brown shale that yields, in addition to occasional
dinosaur remains: ammonites, pelecypods, foraminifera tests, Inoceramus
prisms, carbonized wood, and fish scales, bones and teeth; many species
of fossil plants have also been taken from the Moreno. An excellent
reference to consult regarding Late Cretaceous stratigraphy in Del
Puerto Canyon and neighboring areas (from roughly Hospital Creek south
to Salado Creek)is California Division of Mines and Geology Special
Report 104, 1970, Upper Cretaceous Stratigraphy On The West Side Of The
Northern San Joaquin Valley, Stanislaus And San Joaquin Counties,
California, by Charles C. Bishop. For illustrative images (with
accompanying text) depicting geologic formations exposed in Del Puerto
Canyon, check out http://chem.csustan.edu/geology/kimyai/delpuerto/ .
"Fossil hunter sifts through the years
By Matthew Barrows
(Published June 8, 2000)
"Allan Bennison had always been more interested in bugs than
basketball. As a boy, he collected moths and butterflies, learned the
names of trees and could identify birds on sight.
"Eccentric? There was nobody else out there collecting rocks," says
Norman Bennison, 83, Allan's older brother. "By the time Allan got out
of grammar school, he probably knew as much as the graduate students."
"So it was no surprise to the Bennisons when Allan rode off on a 90-
degree day in 1936 in search of fossilized snails with only a cheese
sandwich and some warm tomato juice in his bike basket to keep him
"And it was no surprise to the family when their 18-year-old middle
son -- the boy who was always a bit different -- pedaled home that
steamy evening, the sandwich and juice gone and a pile of strange bones
in their place.
"The surprise instead belonged to every paleontologist on the West
"Bennison's bones turned out to be the vertebrae and hindquarters of a
hadrosaur, a two-stories-tall duckbilled dinosaur that gathered in
massive herds more than 65 million years ago.
"It also turned out to be the first dinosaur ever discovered in
California. As any paleontologist will tell you, hadrosaurs don't
exactly make dinosaur hunters leap out of their seats. They were so
common and so concentrated in parts of North America that scientists
refer to them as "Cretaceous cattle." Many believe they were the staple
diet of large predators such as tyrannosaur rex.
"But until Allan Bennison rode 30 miles on a second-hand bicycle into
Del Puerto Canyon west of Patterson in Stanislaus County, no dinosaurs,
including hadrosaurs, had been found in the state. And no one was
"The problem was that dinosaurs were land creatures, and in the
centuries before they became extinct, most of California was covered by
the ancestral Pacific Ocean.
"A dead dinosaur would have had to have washed miles out to sea to end
up where Del Puerto Canyon is today. And for someone to actually find
its remains -- well, they'd either have to be incredibly lucky or
"Allan Bennison is now semi-retired, working as a geological consultant
and living in Grass Valley. At 82, he says he doesn't feel like a
pioneer in paleontology and never really considered himself an expert
dinosaur hunter either.
"Yet somehow, the kid on the second-hand bike, the kid who collected
rocks, the one who would disappear on exploring expeditions, kept
coming up with rare finds.
"In 1937, a year after the hadrosaur, Bennison discovered the skull of
a giant prehistoric sea lizard called a mosasaur in a creek in Merced
"The skull is now encased in glass in the natural-history museum at
Sierra College. It's dark like mahogany and sleek, with 68 long,
'"My mosasaur was probably about 20 feet; he was small. They got about
40 feet or so, you know," Bennison said. "If I was out swimming, I
wouldn't want to tangle with that character."
"Dick Hilton, a paleontologist with Sierra College, said the fossil --
dubbed Plotosaurus bennisoni -- is still the best-preserved mosasaur
ever found in California.
"The California Academy of Sciences in San Francisco and the Berkeley
Natural History Museum also house many of Bennison's fossil finds. But
it was in a much smaller museum that the Bennison collection got its
"Contrary to older brother Norman's recollections, there were other
boys who collected rocks and fossils in Pacific Grove, the town by
Monterey Bay where Allan grew up.
"Allan Bennison says his friends competed over who could come up with
the best discoveries; dolphins' teeth, whale bones, crab carapaces,
fossilized clams were all fair game. He climbed cliffs and combed
beaches, honing his instincts and building an understanding of nature
few adults ever attain.
'"We set up little museums," Bennison said, closing his eyes to see the
past. "They weren't much really. Mine was a little woodshed. I had a
couple of shelves where I kept my best finds. We would trade fossils,
try to upgrade our collections. There was a bit of one-upmanship."
"In 1934, however, the Great Depression dried up the tourism trade in
Monterey. People no longer stopped at his father's service station, and
the family moved inland to a dairy farm near Gustine in Merced County.
"Though Bennison says the influence in Gustine was more on sports than
science, the move put him in a whole new landscape. The rocks near
Gustine were older than the ones along the coast and had more showy
fossils -- ammonites, ancient snails similar to a chambered nautilus --
hidden inside them.
"On the weekends, Bennison would leave the farm at 7 a.m. and seek out
river beds and road cuts, any place where bare rock had been exposed,
any place he could look into the earth and rediscover the past.
"On June 11, that search took him to Del Puerto Canyon, hills 80 miles
south of Sacramento that are a color somewhere between green and gold.
Bennison remembers having trouble pedaling in the heat of the day, but
as he approached the canyon he got a cool boost by the winds that
whistled out of the pass.
'"I remember that it was hot," he said. "Most of the people who talk
about global warming weren't around in the 1930s."
"On a recent trip back to the spot, Bennison points to a run-down ranch
house a half mile from the road, its tin roof rusted brown, the fence
posts slumping. Behind it is the black shale slide Bennison was drawn
to in 1936. He says he went looking for ammonites that day and actually
found one but lost all interest in them when he stumbled, literally, on
the hadrosaur bones.
"UC Berkeley scientists cleaned out the site after he reported the
find, Bennison said, taking back 175 pounds of dinosaur bones and a few
vertebrae of a mosasaur. Bennison is careful to say that his dinosaur
was the first reported to science. As the scientists later discovered,
the rancher who owned the land, a man named John Hammond, had found the
dinosaur's femur years earlier and was using it as a door stop.
"Bennison is 82, but says he feels like he did when he was 42. Once
back in Del Puerto Canyon, he acts like he's 22.
"He stops at the road cuts, runs from the car to the side of the rock
wall and climbs up with rock hammer in hand. He still packs a cheese
sandwich but has replaced the tomato juice with bottled water.
"And he's not finished discovering.
"Dick Hilton says he was fossil hunting with Bennison two months ago in
a creek cut in Bear Valley when Bennison came upon a cream-colored
object about the size of a pea.
"Hilton says he thought it was probably a belemnite, the skeleton of a
squid-like creature, and took it back to his lab. To his amazement, the
object turned out to be a long, rigid tooth of a plesiosaur, a long-
necked sea serpent with paddle-like limbs that vanished along with the
'"So Allan had now found the first dinosaur in California, the best
mosasaur skull and now the first Jurassic plesiosaur tooth from the
state," Hilton says.
"Another discovery. Another surprise. But not to those who know about
Allan Bennison and his never ending search for life inside the rocks."