crinoid stem, ichnofossils, and maybe a hyolith at Etobicoke Creek?

[Monica]

Hi all!

 

Yesterday afternoon I visited my local haunt (Etobicoke Creek, Georgian Bay Formation, Upper Ordovician) with the kids, and I found a few items that I'd like to show you:

 

Item #1: long crinoid stem - any ideas as to its identity?

 

Item #2: big piece with ichnofossils - item circled in yellow is ichnofossil "a" and item circled in orange is ichnofossil "b"

 

Item #2a: ichnofossil "a" top view

 

Item #2: ichnofossil "b" top view

 

Item #2: ichnofossil "b" side view

 

Item #3 top: two views of a mineral stain that has the shape of a hyolith - what do you think?

 

Item #3 bottom: crinoid columnal impressions (I think!) so it is fossiliferous rock (I think!) so perhaps the specimen above could've been a hyolith???

 

Thanks as usual for your help!

 

Monica

[vellis]

15 minutes ago, Monica said:

 

Item #1: long crinoid stem - any ideas as to its identity?

 

I can’t ID your crinoid stem, but that is a NICE one.  I have not seen one all together like that around here. 

[Tidgy's Dad]

Love those crinoid stems, beautiful. 

And i think your ichnofossils may be crinoid holdfasts. 

[Monica]

9 hours ago, vellis said:

 

I can’t ID your crinoid stem, but that is a NICE one.  I have not seen one all together like that around here. 

 

I don't usually find intact stems, either - I usually just come away with columnals in hash plates - so this is a nice find for me, too!  Thanks for commenting! 

 

5 hours ago, Tidgy's Dad said:

Love those crinoid stems, beautiful. 

And i think your ichnofossils may be crinoid holdfasts. 

 

Hi Adam!  I thought they looked like crinoid holdfasts, too (especially the bigger one), but I pulled these rocks directly from a bit of exposed wall, and the side I've taken a photo of was facing downwards - could they still be holdfasts if they were oriented downwards when found?

[Tidgy's Dad]

53 minutes ago, Monica said:

 

I don't usually find intact stems, either - I usually just come away with columnals in hash plates - so this is a nice find for me, too!  Thanks for commenting! 

 

 

Hi Adam!  I thought they looked like crinoid holdfasts, too (especially the bigger one), but I pulled these rocks directly from a bit of exposed wall, and the side I've taken a photo of was facing downwards - could they still be holdfasts if they were oriented downwards when found?

Well, I don't know enough about the crinoids in your deposits, but I am aware of crinoids that anchored to the underside of objects and dangled down and of others that attached to the underside of corals and curled around and upwards like these Wenlock examples fixed to the underside of the coral Thecia. 

(sorry, I don't have any close-ups) 

[vellis]

The other thing that I am thinking is does them being “downward when found” necessarily correspond to where they were pre-fossilization?    

 

I’m thinking that stuff can go  up, down, and all around from where it originally was, be it ocean currents or whatever else may move them.  Just a thought.

 

 

[connorp]

Is there any relief to any of the mineral stains?

[Monica]

17 hours ago, connorp said:

Is there any relief to any of the mineral stains?

 

I think there is relief (when I close my eyes and run my finger over it, I think I can feel a change in height, particularly on the edge closest to the ruler - it's the part that's a little darker than the centre of the stain), but if there is indeed relief, it's very subtle.  In the centre you can see a "bumpy" bit - that is definitely a different height from the surrounding stain.

 

I don't know whether it's anything at all - I just saw it, and it struck me as such an odd shape for a mineral stain, so I picked it up, gave it a wash, and then played show and tell here on the forum.  If it's determined to be nothing, then I'll just bring it back to the creek the next time I visit.

 

Thanks for chiming in!