Geoscience Reference
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of one of the most famous walking routes in Australia, The Great Ocean Walk. In
fact, this trail inspired me to dub, tongue-in-cheek, my excursion along the Victoria
coast as “The Great Cretaceous Walk.”
On Monday, June 14, 2010, we were not visiting Milanesia Beach to hike or
enjoy the bucolic countryside. Instead, Tom Rich, local guide Greg Denney from
the nearby town of Apollo Bay, and I were there to look for fossils from the Early
Cretaceous Period, at about 105 million years ago. The landscape was certainly
very different back then. It was a time when Australia was close to the South Pole,
and dinosaurs presumably walked across broad floodplains of rivers that coursed
throughitscircumpolarvalleys.Sincethen,Australiahaddriftednorthandnowwas
just below the equator. Of course, many animals and plants native to the place had
gone extinct, whereas some lineages evolved into the distinctive life of Australia
today,suchasitsrichdiversityofmarsupialsfoundnowhereelseintheworld.More
than a hundred million years can really change a place.
Milanesia Beach, though, was a new place for me, and it might as well have
been new for Tom, as he had not visited it in more than twenty years. His main
reason for looking at its rocks was for fossil bones, especially those of dinosaurs or
smallmammals.Asanichnologist,Iwastheretolookfortracefossils.Iknewmost
of these vestiges of life would consist of burrows and trails made by invertebrate
animalslikeinsects,crustaceans,orworms.Butifwewerereallylucky,theserocks
might also reveal trace fossils of vertebrates, such as the burrows or tracks of mam-
mals, dinosaurs, or other backboned animals.
Unfortunately,duringtheprecedingthreeweeksoffieldworkIhadonlyfound
a few invertebrate trace fossils (burrows) and no vertebrate trace fossils: no tracks,
nests, burrows, toothmarks, gastroliths, coprolites, or anything else that might tell
of a former vertebrate presence. Similarly, Tom had not yet found a single scrap of
bone. We seemed more than due for a big break.
More Bones than Traces
