Crinoids - type and dating

[Dimitar]

Hello guys!

 

I am trying to get a better dating and hope this crinoids may give some information.   Location: Ile Bizard, North Shore at Lac Deux Montagnes.

 

N.1

 

N.2 (same)

 

N.3

 

N.4

 

N.5

 

N.6

 

 

N.7

Edited May 15, 2021 by Dimitar

[Dimitar]

It could be also Sponge: Porifera

 

https://en.wikipedia.org/wiki/Hexactinellid  (sponges)

Hexactinellida (Sponge)

[Dimitar]

On 5/15/2021 at 10:34 AM, Dimitar said:

 

Any opinion about these balls? I am suspecting to be Hexactinellida (Sponge) .

[Rockwood]

Possible they are poorly preserved calyces with enrolled arms, of flexible crinoids ?

[Dimitar]

16 hours ago, Rockwood said:

Possible they are poorly preserved calyces with enrolled arms, of flexible crinoids ?

These seems to be predicessors of crinoids. My estimation for the time could be wrong. It could be Ediacaran or pre-cambraian.  It is sitting on top of sandstone ( possible Potsdame) , bellow there is little or almost nothing.  The level with these balls is very well preserved and there are plenty of examples on the site. The site is big enough. It is the Northern part of ile Bizard. 

Here is another small example that I took today:

 

[Ludwigia]

Just to get things straight for you. As already indicated by others in some of your previous posts (one of which has mysteriously disappeared), you won't be finding any Ediacarian or Precambrian sediments on Ile Bizard.

[FossilDAWG]

The little plated balls are a species of paracrinoid called Malocyctites murchisoni.  These are abundant in parts of the Chazy formation exposed on Ile Bizard.  I used to collect these when I lived in Ottawa.  Other interesting echinoderms occur in the formation as well.  There are also small bioherms (sort of like reefs) made of bryozoans.  Brachiopods such as Mimella and sometimes straight shelled nautiloids are also common.  These are middle Ordovician, not Precambrian or Cambrian in age.

 

Don

[Dimitar]

59 minutes ago, Ludwigia said:

Just to get things straight for you. As already indicated by others in some of your previous posts (one of which has mysteriously disappeared), you won't be finding any Ediacarian or Precambrian sediments on Ile Bizard.

Thanks!

The other topic was moved to Questions & Answers. Then I tried to use "Hide" admin function , but it seems to completly deleted the topic. I was not intending to delete/ just to hide it from top of the list.

 

So far, what I learn -  there are some rocks that are called Potstam sandstones and post-Potsdam sandstones.  Such are the stones on North shore of Montreal.  There is little or almost no fossils in these stones and they are said to be pre-cambrian.  If I see such rocks on the Northshore -  it is quite possible to see the same type of rocks on the South shore - Montreal and Laval.  The excelent opportunity in Ile Bizard is that I can see there many layers on top of each other.  I will visit some other places and that will allow me to have more options to compare.

 

Thanks,

Dimitar

[Ludwigia]

43 minutes ago, Dimitar said:

So far, what I learn -  there are some rocks that are called Potsdam sandstones and post-Potsdam sandstones.  Such are the stones on North shore of Montreal.  There is little or almost no fossils in these stones and they are said to be pre-cambrian. 

 

 Potsdam Sandstone is middle to late Cambrian and not Precambrian.

[Dimitar]

3 hours ago, FossilDAWG said:

The little plated balls are a species of paracrinoid called Malocyctites murchisoni.  These are abundant in parts of the Chazy formation exposed on Ile Bizard.  I used to collect these when I lived in Ottawa.  Other interesting echinoderms occur in the formation as well.  There are also small bioherms (sort of like reefs) made of bryozoans.  Brachiopods such as Mimella and sometimes straight shelled nautiloids are also common.  These are middle Ordovician, not Precambrian or Cambrian in age.

 

Don

Thanks a lot Don!  Great answer!

I was sure these are not crinoids, because ossicles were missing.

(Ossicles are small calcareous elements embedded in the dermis of the body wall of echinoderms. ) - the disks.

However it is not far from the crinoids and similar to them.  Possible before crinoids. So your answer is perfectly matching to my expectations. 

 

On the site in ile Bizard, I think we have also Cambrian and some pre-Cambrian, because many layers are visible there and there is a clear difference from one layer to another. The first layers at the bottom - near the water - I don't find much or any signs of life. Then I see some possible Cambrian explosion. Then the Ordovician - this is the layer where I took these little plated balls. On top of it there are many other layres- there is 2 meters of sediments - then we see the colision and that's the top,  last time or near that time, when the sediments stopped to accumulate there.  Knowing the age of these balls is good to have an idea what time all these processes happened on the site.  

 

Regards, 

Dimitar

 

[Ludwigia]

11 hours ago, Dimitar said:

when the sediments stopped to accumulate there

The sediments didn't stop accumulating. They were swept away ages later by the glaciers. And once again, there are no Precambrian rocks on the surface at Ile Bizard. I'm afraid that some of your assumptions are still quite inaccurate and I would suggest that you turn to a deeper study of the literature on the stratigraphy of the area before your imagination runs away with you.

Here is something to start you off.

[Dimitar]

Today I took another specimen from Ile Bizard, from a different site there on North- East side.  It could be the same type but there are some differences.

 

 

N.1a - from the site

 

N. 2.a - dimensions

N. 3.a

 

N.4.a

N.5a

N.6a

Edited May 20, 2021 by Dimitar

[Dimitar]

I suspect the animal on 5a / 6a is the same animal that create such balls. They are on the same plate. You may see the original rock on N.1a .

[Kane]

12 minutes ago, Dimitar said:

I suspect the animal on 5a / 6a is the same animal that create such balls. They are on the same plate. You may see the original rock on N.1a .

No. Those are likely bryozoans.

[Dimitar]

1 hour ago, Kane said:

No. Those are likely bryozoans.

I found similar balls with bryozoans.

 

Do you think this ball was made by this bryozioan?

 

Quote

Bryozoans grow in several different shapes, branch, mound, bulbous and web shaped. 
These globular shaped Bryozoans were not found in nice neat colonies but broken 
off and fossilized in place.

 

[Dimitar]

It seems the Bryozoans were also able to create similar balls.

 

Another example.

 

(there are several pictures there in the last example, the picture 7/7 is matchig the best )

Edited May 20, 2021 by Dimitar

[Dimitar]

https://geocollections.info/specimen/98592 

 

Trepostomata

The speciment, matching the best to what I have is from Estonia.  

I don't understand why it was not registered first in Canada, because the site that I visited is full of such balls. It is a public parc and anyone looking for such kind of fossils can easily see them. 

Edited May 20, 2021 by Dimitar

[Kane]

No, it looks more like a Fenestella-type of bryozoan. 

 

In terms of where it is first "registered," I think you mean where it is first described. Priority is given to the holotype and its location, with primacy assigned to whoever published the formal description and erects the holotype. But, again, the Estonian species you are referring to only bears a very small resemblance to the piece here on account of them sharing some morphological characteristics typical of this type of bryozoan. 

 

What you ought to do instead is track down the literature of the Chazy Group where it describes the fauna of said group. This is far more preferable to speculation in comparison with farflung examples, based simply on some shared visual similarities.