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Possible Trilobite trace fossil and Coral from Etobicoke Creek


Monica

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Hello everyone!

 

Yesterday afternoon I went out to my usual site (Etobicoke Creek, Georgian Bay Formation, Upper Ordovician) and I found a couple of items that I've not found before...

 

Specimen #1: possible trilobite trace fossil (Have I FINALLY found something that is trilobite-related for certain?!)

 

Etobicoke Creek Fossil 11.JPG

 

Specimen #2: possible coral - the diameter of the corallites (if that's what they are) ranges from 2-3 mm

 

Etobicoke Creek Fossil 12a.JPGEtobicoke Creek Fossil 12b.JPG

 

Thanks for looking!

 

Monica

 

PS - I actually went out with both of my kids yesterday.  Viola (almost 6 years old) found her usual stuff - lost of rocks containing crinoid discs.  It was the first time I took William (3 years old) with me, and he actually found a fossil all by himself - it's just a rock that once had either a small orthocone nautiloid or a piece of crinoid stem in it, but he's pretty proud of himself :)

 

 

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I have seen trilobite traces very similar to the ones you have posted. The second photo certainly looks like corals I have collected. The internal geometry is correct.

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That is what is called a Rusophycus. Basically it's a trilobite burrow that was most likely made by Flexicalymene

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I have a trilo trace fossil very much like those.  

Rusophycus pudicum (trilobite burrow trace fossil)

upper Ordovician Period

Cincinnatian series

Latonia Formation

Kenton County, Kentucky

 

SAM_3471.JPG

SAM_3472.JPG

SAM_3473.JPG

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Yeah, Rusophycus.

And the cxoral is likely a Favosite species. They look like a honeycomb on end, and in the side view they have those segments to them, because they are tabulate corals.

http://www.google.com/search?q=Favosite&btnG=Search&hl=en&gbv=1&tbm=isch

And the thrird photo shows a small piece of bryozoa in the middle left.



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Hi once again!

 

Well, while I was really excited to discover that I had finally found something trilobite-related here in the Toronto area, my daughter was a little disappointed that she still lacks trilobite material in her budding fossil collection.  Consequently, we went out for an hour today, trying to look for more traces of trilobites and I came across something that may be another Rusophycus but I'm far from certain.  I took a quick picture of the specimen this evening, but if it's still too difficult to tell then I can always take a better picture in natural light tomorrow afternoon when I get home from work.  The specimen that I'd like your thoughts on is the one on the left - it feels similar to the ones on the right (which are definitely Rusophycus) because it feels like there are two lobes that border a slight indentation down the middle, and it looks as though there is a little trail/path just below the possible trilobite burrow:

 

DSCN1143.JPG

 

So, what do you think - Rusophycus or just another suggestive rock?  I look forward to your input...

 

Thanks again!!!

 

Monica

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The two on the right definately look like trilobite feeding traces to me. They have the classic "lips" shape to them, and the roughness where the legs were working the silt.

The one on the left is more of a puzzle. I can't see any distinctive features to tie it to a known trace type. I think it is likely to be a fossil something, though.



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  • 3 weeks later...
JUAN EMMANUEL

Hi, I just saw this topic just now. 

For the coral, that is not a native of the Humber Member of the Georgian Bay formation. The Humber Member of the Georgian Bay formation begins itself from the Humber River covering the Mimico and Etobicoke Creeks along the way, and stretches to the lowest part of the Credit River in Mississauga. It is not until you hit the Streetsville Member on the Credit that one can start finding corals. The Humber Member is more known for having a rich pelycopod fauna and that coral you showed looks foreign. 

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On 10/27/2016 at 10:16 PM, JUAN EMMANUEL said:

Hi, I just saw this topic just now. 

For the coral, that is not a native of the Humber Member of the Georgian Bay formation. The Humber Member of the Georgian Bay formation begins itself from the Humber River covering the Mimico and Etobicoke Creeks along the way, and stretches to the lowest part of the Credit River in Mississauga. It is not until you hit the Streetsville Member on the Credit that one can start finding corals. The Humber Member is more known for having a rich pelycopod fauna and that coral you showed looks foreign. 

Hi Juan Emmanuel!

 

Thanks for looking at my finds!

 

I was just wondering - I found a solitary rugose coral along Etobicoke Creek last month - would that also be a "visitor", just like the worn coral posted in this thread? 

 

Thanks for your help!

 

Monica

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Monica,

      Someone on here has a tag line "A fossil is always where its suppose to be", or something along those lines. Not to dismiss documentation on locality, different exposures of rock can be found outside of the where there suppose to be category if that makes sense. Just recently I have found a trilobite that did not really belong in Eastern NY, but I tried discussing it with the Dipleura and it just ignored me and stayed there:). In short there are no definitive answers, I like the burrows by the way and keep hunting that elusive trilobite ya never know.     

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Loose fossils, being washed around into other formations, are called "floats". Documenting where a fossil is found is very important, but it is equally important to document if it was found "in situ" (where it was created) or if it was found out of context as a float.

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"The trilobite ichnofossil looks a lot like Bilobites"

That is a class of trilobites, but how can you tell if one of those made the trace?

"(or even Cruziana/Rusophycus)"

Both of those terms refer to the characteristics of the trace, and the Cruziana is a long trackway, while the Rusophycus is a dig hole that normally looks like a pair of lips. The ones shown here are of the lips type, so would be Rusophycus.

Cruziana http://www.google.com/search?q=Cruziana&btnG=Search&hl=en&gbv=1&tbm=isch

Rusophycus http://www.google.com/search?q=Rusophycus+&btnG=Search&hl=en&gbv=1&tbm=isch

The Cruziana often look like tiny motorcycle tire tracks running across the rock.



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i should have used inverted comma's on "bilobites".

Bilobites is something of a nominum nudum.It used to be the brachiopod Dicoloesia.

I think it has been used very infrequently(can think only of Lebesconte and Yin),and mostly informally,to indicate a measure of uncertainty between naming the ichnite

Cruziana or Rusophycus).

Seilacher(in Crimes and Harper,Trace Fossils,Seel House Press,1970) has made a great inventory of the breadth of the taxon Cruziana(more recently,Sadlok,

on C.semiplicata).

A lot of Cruziana are cast on turbidite sole beds,so preservation varies

Cruziana has also been found in non-marine basins(e.g.Triassic of Greenland).

Some echinoderms make bilobed traces as well,btw

 

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