Fossil walk- Ulladulla

Ulladulla- Gondwana Coast Fossil walk

On the 10^th April I was very tired and couldn’t handle full-on bushwalking/ birding and wanted something different. The Ulladulla fossil tour sounded intriguing, but it only mentioned summer. Luckily they now have tours year round although these depend on the tides, which makes it tricky. Interesting birds were 3 white faced herons and masked lapwings fossicking through the seaweed at low tide. Plus common terns, rainbow lorikeets and king parrots flying over, although I only recorded 7 bird species.

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After an interesting overview of the geology, climatology and biology by Phil Smart (or volunteers) (where you get a brochure, Timescale bookmark and soil particle size pamphlet which are pretty handy) we set off to the Ulladulla harbour rock platforms. Check out their website for a better overview than mine and photos http://gondwanacoastfossilwalk.com.au/

 

,The rock platforms show multiple siltstone layers which were deposited about 273- 269 Mya (the Wandrawandian siltstone). They contain many Many fossils of mainly bottom dwelling species, from calm, cold water (ie when Australia was Gondwana and over the Antarctic). Many of these species (~95%) became extinct in the great Permian extinction. The most beautiful fossils were of the Sea fans and sea lilies (Crinoids, ie related to starfish) as these look like the cells of a plant when under the microscope. I also liked the shells that look like Bivalves (but are Brachiopods) called the Productids as you can see the tiny holes in the fossil layers from their spiny shells. My invertebrate text book says that of 26000 Brachiopod fossil species only 335 still survive.

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Dropstones were pretty bizarre, ie stones (some very large >50cm) embedded within the siltstone layers, which had probably travelled many km from the mountains within glaciers. I was surprised that I also found the Glendonites interesting, these large crystals and crystal clusters, form in <5 degree temp water in organic rich silt. Cannon ball secretions (calcium carbonate, iron carbonate, silica) form around another object, whether it be a fossil, glendonite, or drop stone.

Phil showed how the harbour’s cliffs also had huge ripples in the otherwise flat rock layers and explained how these were formed due to earthquakes rather than continental drift. Whereas the tessellation (ie tile like) pattern of the rock platforms are likely to have been formed due to geological rifting when NZ separated from Australia ~80mya. It was interesting to see what made Australia and all its species.

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My Buddy and I travelled 22 hours to see the wall of dinosaur footprints in Bolivia and 2 days to see ‘Lucy’ in the Serengeti yet one of the best fossil displays I’ve seen is on our doorstep in Ulladulla. I encourage you to go if you can and I think they have tours over Easter. The main problem with the tour is the tides and the weather.

Benj Whitworth