Mystery to me

[Georgie87]

Any help identifying what these are would be very much appreciated. I have found a few trilobites, bivalves, among others in the Whitby Formation on the shore of Lake Ontario. I'm just really unsure of what these could be. Thank you in advance.

[Kane]

The first one looks like a piece of a nautiloid, possibly Geisonoceras. Nice finds!

[GeschWhat]

The first one looks like a bit of a cephalopod, but best wait for the experts.

 

Welcome to the forum!

 

EDIT: Typed too slow...Kane beat me to it, but he is one of those experts.

[Innocentx]

The reverse looks a bit like calamites bark. Not sure if it would be out of the question for a marine fossil and a bit of plant to be nearby eachother.

[Kane]

1 minute ago, Innocentx said:

The reverse looks a bit like calamites bark. Not sure if it would be out of the question for a marine fossil and a bit of plant to be nearby eachother.

Not out of the question at all; woody bits that drifted out to sea and became water-logged occasionally made their way to marine sediments. Of course, that is more in the Devonian. Because it wasn't stated earlier (mea culpa), these are Ordovician shales. In this case, the second piece resembles the impression of a bivalve, methinks. 

[FossilDAWG]

There are no Carboniferous rocks, marine or terrestrial, in southern Ontario or anywhere to the north along the path glaciers would have been able to transport material.  This excludes Calamites as a possible ID.

The lithology and fossils suggests these came from the Upper Ordovician Whitby Formation, as Georgie87 stated.   The "Calamites" is likely a fragment of the exterior of an orthoconic nautiloid.  The other specimen is of course an internal mold of an orthoconic nautiloid.  Historically they have been called Geisonoceras, but there is little morphological data to support that assignment.  Bob Frey reassigned these fossils years ago; I'll have to check (later) but I think it was in one of the USGS volumes on Cincinnatian fossils.

 

Don

[westcoast]

Agree with fossildawg, both are nautiloid, the second being an impression of the external ornament

[KimTexan]

I like the orthoceras cepholopod.

 

I am not sure how good the Ordovician atlas is on this site, but I have used the Pennsylvanian one and it has been quite helpful at times. The region within the atlas is not from Lake Ontario region though. Hope it can be of some help.

http://www.digitalatlasofancientlife.org/