Fossilised coral from Mornington Australia

[Gavin Rayner]

My first visit to Fossil Beach at Mornington Victoria today. I found this piece of fossilised coral. I know the finds from this area date to the Middle Miocene period (10-15 million years old) but I was curious as to whether this would date from that period too?

 

Edited August 3, 2019 by Gavin Rayner
Couldn’t access photo library

[digit]

Ah, this was found right around the bend from the famous fossil site at Beaumaris. Other than having the opportunity to collect there once a few years back, I'm not an expert in this area. I do know that there is an excellent guide available online to the fossils of Beaumaris and this may apply to where you found your piece of coral.

 

https://www.bayside.vic.gov.au/sites/default/files/beaumaris_fossil_book_museum_victoria.pdf

 

Additionally, we have members who know that area and perhaps they will chime in. @DanKurek @Paleoworld-101

 

 

Cheers.

 

-Ken

[Gavin Rayner]

Thanks Ken,

 

I have visited Beaumaris a few times, it’s only about 35 kilometres between the two sights. The book “Fossils of Beaumaris” suggest the Beaumaris fossils are between 6 and 5 million years old. 15-10 million years ago is a long way off  6-5 million years ago. I suppose the only way to know, would be to know which layer it came out of.

 

Cheers,

Gavin

Edited August 3, 2019 by Gavin Rayner

[Paleoworld-101]

Fossil Beach at Mornington mainly exposes the Gellibrand Marl (previously Balcombe Clay, which looks like a darkish grey clay), which yes, is approximately middle Miocene in age (at least 15 million years i believe). I would guess that is where this came from too. Did you also find lots of gastropod shells too? 

[Gavin Rayner]

Hello Paleoworld-101,

 Thanks for the info. I didn’t really know where to look, should’ve done my homework. The piece of coral is the only thing I found on the day. I did notice soft grey clay extending from the cliff face towards the shore, and also the cliff appeared to be dry clay. Where did you find your fossil shells? Did you need to dig into the clay?

Cheers, Gavin

 

[Dan 1000]

@Gavin Rayner G'day! 

 

As Paleoworld has previously stated, the fossils collected from Fossil Beach are around 15 million years in age. Besides corals, numerous gastropod and bivalve fossils can be found there as well as some rare sharks teeth. There is a section of the beach where there is an exposure of grey clay which extends down to the water. This is where the fossils can be found. You can see some of the shells potruding out of the cliff and they are fine to collect. Despite there being no restriction on digging in the cliff, I would advise against it as the cliffs can be rather unstable especially after rain. Plently of fossils can be found washed out at the base of the cliffs or in the shore platform. The clay is rather soft so I would bring a small tool such as a screw driver to try and dig the shells and other fossils out of the platform and fallen rocks. 

 

Here is one of the largest shells I have ever found from the site (Umbilia eximia?) after a cliff fall

 

Hope this helps,

Dan

[advertex]

Hello Gavin, What you have found is actually not a fossil at all, rather a recent temperate water species of coral called Plesiastrea versipora, which is moderately common in parts of Victoria and has a fairly wide distribution. You will notice that the calcium carbonate has not been pseudomorphically replaced and should actually be harder than most of the fossils you will find from this area. Regarding the renaming of the Balcombe Clay: - I don’t personally agree with the replacement of the Balcombe Clay with the Gellibrand Marl, as the species composition and age of the type location for the Gellibrand Marl is quite different to that of fossil beach. However, there is a location nearby, which is tantamount to the Gellibrand Marl and I can only assume this is why it was changed? The Gellibrand Formation undeniably one of the more prominent formations of the Miocene period in Victoria and according to The Australian Stratigraphic Units Database; the Gellibrand Marl, replaces the Gellibrand Clay (Bock & Glenie 1965), which incorporates the Fishing Point Marl, the "Upper Glen Aire Clay" of the Otway Basin and the Heytesbury Group and Torquay Group (VandenBerg 2009). Only in the Torquay Group does the Gellibrand Marl replace the Fyansford Clay (of Bowler 1963, Chapman & Cudmore 1924, and others) although this appears to be reinstated in the latest version of the Geology of Victoria by (William D. Birch 2003). Ergo should the Gellibrand Marl be restricted to the Otway Basin??The Fyansford Formation was originally described as the Newport Formation (Thomas & Baragwanath 1950). Although the name Fyansford Formation was considered more applicable to the widespread contemporaneous marine strata throughout the Port Phillip Basin (Abele et al., 1988) Would be great to see more finds from members from this area!
 

[Gavin Rayner]

On 12/08/2019 at 6:25 PM, DanKurek said:

@Gavin Rayner G'day! 

 

As Paleoworld has previously stated, the fossils collected from Fossil Beach are around 15 million years in age. Besides corals, numerous gastropod and bivalve fossils can be found there as well as some rare sharks teeth. There is a section of the beach where there is an exposure of grey clay which extends down to the water. This is where the fossils can be found. You can see some of the shells potruding out of the cliff and they are fine to collect. Despite there being no restriction on digging in the cliff, I would advise against it as the cliffs can be rather unstable especially after rain. Plently of fossils can be found washed out at the base of the cliffs or in the shore platform. The clay is rather soft so I would bring a small tool such as a screw driver to try and dig the shells and other fossils out of the platform and fallen rocks. 

 

Here is one of the largest shells I have ever found from the site (Umbilia eximia?) after a cliff fall

 

Hope this helps,

Dan

Hey Dan thanks for taking the time to respond with some very helpful information. I’m looking forward to getting back to Mornington with some more knowledge. Cheers, Gavin

Edited September 21, 2019 by Gavin Rayner

[Gavin Rayner]

On 04/09/2019 at 5:46 PM, advertex said:

Hello Gavin, What you have found is actually not a fossil at all, rather a recent temperate water species of coral called Plesiastrea versipora, which is moderately common in parts of Victoria and has a fairly wide distribution. You will notice that the calcium carbonate has not been pseudomorphically replaced and should actually be harder than most of the fossils you will find from this area. Regarding the renaming of the Balcombe Clay: - I don’t personally agree with the replacement of the Balcombe Clay with the Gellibrand Marl, as the species composition and age of the type location for the Gellibrand Marl is quite different to that of fossil beach. However, there is a location nearby, which is tantamount to the Gellibrand Marl and I can only assume this is why it was changed? The Gellibrand Formation undeniably one of the more prominent formations of the Miocene period in Victoria and according to The Australian Stratigraphic Units Database; the Gellibrand Marl, replaces the Gellibrand Clay (Bock & Glenie 1965), which incorporates the Fishing Point Marl, the "Upper Glen Aire Clay" of the Otway Basin and the Heytesbury Group and Torquay Group (VandenBerg 2009). Only in the Torquay Group does the Gellibrand Marl replace the Fyansford Clay (of Bowler 1963, Chapman & Cudmore 1924, and others) although this appears to be reinstated in the latest version of the Geology of Victoria by (William D. Birch 2003). Ergo should the Gellibrand Marl be restricted to the Otway Basin??The Fyansford Formation was originally described as the Newport Formation (Thomas & Baragwanath 1950). Although the name Fyansford Formation was considered more applicable to the widespread contemporaneous marine strata throughout the Port Phillip Basin (Abele et al., 1988) Would be great to see more finds from members from this area!
 

Thanks Advertex for such an in depth response. It’s really appreciated, even though you did burst my bubble  Hopefully I’ll be heading back to Mornington soon with a bit more knowledge. Cheers, Gavin