The Lower Cambrian Emu Bay Shale of Kangaroo Island, South Australia has long been famous as a source of specimens of trilobites. The reference genus identified in 1956 by Dr. B Daily, Adelaide University, were named Emuella after the area. Emu Bay is additionally important as the only site in Australia so far to yield a Burgess-Shale-type biota. Fossils of the Emu Bay Shale Biota preserve minute details of early animals with and without mineral skeletons. These fossils preserve not only body outlines, but also gut contents, appendages and even eyes. Together with tiny shells and other microfossils from Cambrian rocks of South Australia, the Emu Bay fossils document the rapid evolution of marine life following the extinction of most Ediacara fossil groups. Based on the calibrated 2012 Geologic Time Scale, the age of the Emu Bay Shale is 514 ± 1 Mya.
The rocks exposed on this stretch of coast line from the Emu Bay jetty west to Cape DÉstaing is a listed fossil reserve. A similar reserve exists on the opposite eastern side of the bay. The important type section is exposed at the listed coordinates. Emu Bay Shale is grey/brown fissile shale. The rock is rich in fossils. It seems likely that the animals owe their preservation to rapid burial in stagnant mud. These rocks are commonly ripple marked and sometimes show trilobie tracks and casts. The Emu Bay shale is overlain by cross bedded pink feldsparic sandstones of the Boxing Bay formation.
Please visit the two earthcache sites, the listed coordinates and the nearby waypoint. Study the rocks and report your answers for the following tasks. DO NOT ATTEMPT TO REMOVE ANY OF THE ROCKS. Send your answers to the cache owner.
- Describe the rock at the listed coordinates. Do you see any fossils? Ripple marks? Layers? Polygon checkerboarding?
- Describe the rock at the waypoint coordinates. Do you see any fossils? Layers? Colours.
Estimated location Emu Bay 500Mya.