Dinosaurs in the Otways

Otways Timescale

For many years palaeontologists, locals and tourists alike have been finding and unearthing a rich history of dinosaur remains along the coast of Victoria and hardly anyone knows about it!

The Otway Ranges Coastal Cretaceous site extends all the way from Lorne to Moonlight Head. Most of the locations were found by luck with someone spotting a bone sticking out of a weathered rock as they walked past. Not all localities are created equal, however, and one of the best is a site called Eric The Red West (after a shipwreck back in the 19th Century) located near the Cape Otway Lightstation. Scoped out in 2011 and, with the discovery of a fossil bearing conglomerate exposed at surface, plans began for a three-week dig in 2014 (see at the point in the image below).

Otways
a. Inset map showing the position of The Otways within Victoria. b. Geological map of the region, showing the Cretaceous Rocks with some of the major Cretaceous fossil sites. Source of fossil localities.

Although this is not strictly a field-trip guide like others you’ll find on this site, this is indeed a significant geological location and the site of numerous fossil digs and very current research. I myself have participated in two digs down at the Otways (see the dorky ‘look at my fossil!’ photo below).

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Overly excited at probably finding a bunch of ‘shoulder bones’ (you throw them over your shoulder because they ain’t worth keeping)

As indicated in the first image, the fossils being dug out of the ground are from the Early Cretaceous. At this time (~120 Ma), Australia had begun it’s journey north at the rate your fingernails grow, with the formation of a large rift valley separating it from Antarctica. When the dinosaurs were walking around Victoria it was cold, really cold. In fact, Victoria then was located inside the Antarctic Circle, enduring at least three months of complete darkness annually.

This leads us to many of the questions we are trying to answer – how did they live? Did they have special adaptations? Did they have feathers? Why did they die? That is why it is important to extract the rocks from these coastal sites – to paint an accurate picture of Victoria in the Cretaceous.

snow
Were the dinosaurs wondering around in the snow? Source.

The site is comprised of arkosic sandstone, claystone and mudstone – once part of a large flood plain. Fast-flowing waters carrying debris from the forest floors would travel down into a large river valley formed as a result of the rifting (east-west). Little bits of broken plants and bones got caught up in large trees and stumps – signs we look for when we’re out in the field.

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Here I am knocking off moss and other slimey-s in order to get to the rocks beneath and see the good stuff (2014).

The fossils are contained in a cross-bedded fluvial sandstone and clay stone which also contains plant fragments up to tree size, charcoal clasts (you can see this in the first image), volcanic rock and tree roots. It’s not like the movies – you don’t just brush the sand away from a huge articulated skeleton. The bones are smaller and often broken, so you have to use a hammer and chisel to break hard rock down into tiny pieces – it’s hard work!

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The instruments which I used at the dig last year – notice there aren’t any dainty paint brushes?

Spotting bone in amongst all of the other material is no easy task, and in reality there’s probably a lot which are missed. Mostly what we’re looking for is a bit which is shiny (enamel), or distinct with sharp edges, a brown colour or a much softer material. Whilst we find bits of turtles and birds, fish, plesiosaurs, pterosaurs, big T-rex-relatives and tiny chicken-sized dinosaurs, the real interesting fossils at this site – the ones the are looking for – aren’t dinosaurs… they’re mammals! Tiny, tiny mammals. And we’re after fragments of their jaw. We’re talking millimetres..

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Can you guess what part is the fossil? It’s one I spotted in 2014. Source

In 1986 two dinosaur tracks were noticed in the Eumeralla Formation at Skenes Creek (point 3 in the map above).  These dinosaur tracks have been removed and stored at Museum Victoria for study, along with tracks discovered earlier at Knowledge Creek. The tracks are thought to have been made by small ‘hypsilophodontid’ ornithopods akin to Leaellynasaura which was discovered at Dinosaur Cove. These tracks show that dinosaurs actually lived in these palaeoenvironments. All of the fossils found at sites like Eric The Red West have been deposited there in fluvial Channels or during floods.

footprint
Photograph of one of the footprints discovered on a raised marine platform between Skenes and Browns Creeks. Source.

Each field season there are literally hundreds of separate fossils which are carefully wrapped up in newspaper, labelled and catalogued on site. The fossils are taken to the Melbourne Museum, where they are carefully unwrapped, examined with a microscope and ‘triaged’, with interesting specimens being selected for preparation. I’ve also been lucky enough to work on the prep-side of the whole process. In the lab we use glues, consolidant chemicals, acids, extraction tools including air scribes and rods, and microscopes, among other tools.

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Volunteers in the dig crew come from all walks of life – not just palaeontologists and geologists – tradies, home-makers, writers, artists, grandmas, students.. all with one thing in common: enthusiasm for fossils. We all eat together, camp together, break rock together, huddle when it gets cold, take advantage of swim-o’clock when the sun comes out and challenge each other for the most creative ‘I found a fossil!’ photos.

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2014 dig crew pretending to be… Velociraptors?

The Dinosaur Dreaming dig crew maintain a blog  where you can keep up to date with the digs and fossil finds. You can also become a friend of dinosaur dreaming, where you will be given the opportunity to come down and visit the site, as well as attend a friends evening at Melbourne Museum to meet the crew and receive a copy of the official field report! If you’re visiting Melbourne Museum, you can also just pop into the Discovery Center to have a chat with staff about the dig.

The BBC featured the ‘spirits of the ice forest ‘ in episode 5 of  Walking With Dinosaurs.

There are plenty of great things to see at the Otways asides, with the Great Ocean Walk (100km long) passing through the national park, a number of beautiful walks under ancient trees leading to beautiful waterfalls. If you’re travelling through the Otways, plan a visit to the Cape Otway lightstation, to see a of Victoria’s important recent history.

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