Ceph Colony ? From Newmarket, Ontario

[Krazy Rick]

I found this one, after looking around awhile, & not finding much ..... I was about to give up; and this caught my eye ...... it's interesting .... whatever it is !! ( Rock is 7" x 4" )

[Northern Sharks]

It's a coral. Where in Newmarket did you find this??? I grew up there and still live a short distance away

[Krazy Rick]

It was in a park,my nephew took me there ..... the Holland marsh park ? .... or something like that .... it was about 10-15 minutes from Davis & Main. It was just sitting in a forest area; barely covered.- Thanks for the ID ....what type of coral would it be ?

[Krazy Rick]

I looked it up, it looks like its Tabulate Coral !!

[Ludwigia]

Maybe Favosites?

[FossilDAWG]

Given the location, Foerstephyllum halli would be a reasonable guess. Foerstephyllum is exceptionally common in "Black River" formations such as the Bobcageon and Gull River. It is the dominant tabulate coral (by far) in the Middle Ordovician in Ontario, and is often seen in rocks used in landscaping as well as in natural outcrops. You wouldn't encounter Favosites until the Silurian, which is exposed pretty far West of Newmarket.

People will often call virtually any "honeycomb coral" Favosites, but the situation is much more complicated than that. Internal structures, such as primary and secondary septa, whether or not the septa are developed into spines, the spacing and shape of tabulae (are they flat, do they curve up or down), the nature of the wall between individual corallites, and the presence and location of pores connecting corallites are all critical to an accurate ID. For example, Foerstephyllum lacks pores, whereas pores are present in the corners of the corralite walls in Favosites, and they are present in the flat areas of the walls (but not the corners) in Paleofavosites. Other genera are distinguished by the uniformity of corallite sizes; the coralites are fairly uniform in Favosites, but in Lecfedites (a Devonian genus) some corallites are much larger than the rest, and are almost round instead of hexagonal. Other Ordovician "honeycomb corals" include Favestina, Cyathophyllum, Trabeculites, Nyctopora, Lyopora, Lichenaria, and Calapoecia, but these can be distinguished from Rick's specimen on the basis of corallite size or shape, the absence of long septa, meeting or almost meeting in the center of the corallite (as in Favestina and Cyathophyllum), and the wall structure (much thicker in Calapoecia and Nyctopora).

If you find a "honeycomb coral" with tabulae and short septa, and with uniformly sized corallites, in the Devonian or Silurian it is likely (but not certain) to be some species of Favosites. In the Ordovician it is likely to be something else.

Don

Edited October 30, 2013 by FossilDAWG

[Ludwigia]

Don. Thanks for the explanation. Very helpful!

[Krazy Rick]

Thanks Don - this is great, to know what I have here - much appreciated !!