Prospecting "Down Under"
In May of 1989, I got the chance to visit the place that I'd always said was my first choice of a faraway destination: Australia.
Fortuitous circumstances had placed two pairs of my friends down under that year. Nancy and Alex were living in Sydney while
he worked on an overseas assignment for his company. Jordan and Ruth were spending the year in Adelaide on a teachers'
exchange program. So I figured it was the perfect time for me to visit the southern continent.
After a short stopover in New Zealand, where I explored Auckland and the hot springs at Rotorua, I landed in Sydney on a
crystal blue morning. I was greeted by Nancy, who told me that it had been raining for three months straight until that very day. (It's
nice to live in Colorado and take its sunny weather with me when I travel; the same thing happened three years later when I
visited London.) I spent a week there exploring such places as the Australian Museum, which has a very nice set of dioramas
on prehistoric Australia, and the Royal Botanic Gardens, with its extensive plantings of native and exotic cycads. My interest
in cycads goes back to my readings about Mesozoic landscapes when I was a kid; I have been growing the living cycads
as houseplants since I got my first apartment, and have been a member of the Cycad Society since its founding in 1977. I got my
first chance to see cycads growing in their native habitat when we visited Kur-in-gai National Park about an hour's drive north of
the city. I also toured the reptile park at Gosford, which houses a nice variety of the native goannas (varanid lizards), other reptiles,
and two of only ten duck-billed platypuses in captivity, named Eb and Flo. Then it was on to Adelaide to visit Jordan and Ruth.
I had met Jordan through the Western Interior Paleontological Society
(WIPS), an organization based in the Denver area
where we both reside. Jordan is one of the founders of WIPS and has been fossil-hunting in the States for over three decades, so
of course, when he got to Australia, he had to check out the rocks. By the time I arrived, he knew all about the local geology
and paleontology. He took me to the South Australian Museum, not as big as the one in Sydney, but quite interesting nevertheless.
It has three huge skeletons of (modern) whales hanging from the ceiling in the lobby. We also visited the botanical gardens
in Adelaide and saw more cycads. I shared my knowledge of these fascinating plants with him, just as he had shared his expertise
in invertebrate paleontology with me when we first met. He also took me to the University of Adelaide geology department, where
he was teaching, and showed me their nice collection of Ediacaran fossils. But what we both really wanted to do was spend some
time outdoors collecting our own fossil specimens.
Adelaide sits in a jewel-like setting on the west coast of South Australia's bulge, at the east end of the Great Australian Bight.
To the north are Lake Eyre and the parched outback basins; to the east, fertile wine country and the eucalyptus-cloaked hills that
divide the Murray River drainage. Jordan and I set out to hunt fossils on one of those bright, clear winter days when the Southern
Ocean mirrors the turquoise sky and the beach begs to be experienced barefoot.
Driving south from Adelaide, we stopped at Hallett Cove. Here, the bedrock is sculpted into monolithic forms which rise out of
the sands like beached whales. And, like marine mammals carrying the scars of their encounters with propellers, these massifs,
too, bear striations on their backs; these not from human intervention, but as testimony to the glaciers which crawled across the
southern hemisphere during the Permian. Boulders frozen in the base of the ice sheets ground grooves in the bedrock as they bulldozed
a path northward from Antarctica (then joined to Australia).
We continued south along the shore to Maslin Beach. Here, vermillion cliffs bisected by the Hallett Cove Sandstone flank a
narrow beach that is licked by constant breakers. The Hallett Cove conformably overlies the limestone of the Eocene-Oligocene Port
Willunga Formation and the clays and sands of the late Eocene Blanche Point Formation. Near where we parked, a lone
eucalyptus tree stood as a sentinel overlooking the ocean. Streamers of ice plant, a mesembryanthemum or "living rock" plant, cascaded
down the hillside, covered with pink and white aster-like flowers. Here the sediments of the Blanche Point look soft enough to
crumble in your hand, and tempt you to reach up and pluck out the globular echinoid fossils that pepper the cliff face...and in a few
places, you can. But when we tried to use a golf ball retriever to net some of the fossil urchins just out of reach, we discovered that in
other places the rock is cemented like, well, cement -- with the same calcite that has filled the interiors of the shells with crystals.
The golf ball retriever was useless, and we had to break out our rock hammers.
Thus armed, the ancient sea floor yielded its entombed inhabitants to us. Our collecting was done in the Tortachilla Member of
the Blanche Point, a sandy-ferruginous limestone near its base. Common are the heart urchins, and the sediment is littered
with millions of their detached spines. We also collected some clams. The fauna has been interpreted as representative of a
shallow-water marine benthic community; during the Eocene, this area was part of the St. Vincent Basin on the passive margin of
the Australian plate, and is thought to have had limited communication with the open ocean.
It took us about two hours to collect all the fossils that it is practical to stuff into your luggage on an international flight,
where baggage limitations force paleontological treasures to compete with the obligatory presents for the in-laws. Then we climbed
the hill back to the car and went off to hunt kangaroos (with a camera, of course).
