Ordovician stromatolites

[Anitafranklin]

This specimen was found on Beaver lake in northwest Arkansas. The road grader has uncovered what I believe is a reef area. This is one of the larger pieces. Many are round like this one which is about 10". Any thoughts on this?

[doushantuo]

Well.......er,you obviously have your own ideas about the piece

Looks like some sort of algal oncoid(girvanella?),xenomorphic on a brachiopod valve,which has since disappeared?

Edited June 4, 2016 by doushantuo

[ynot]

Looks like stromatolite to Me!

Nice find!

What else did You find in this "reef"?

Tony

[Pumpkinhead]

It could be a stromatoporoid as well

Edited June 4, 2016 by Pumpkinhead

[doushantuo]

Whatever it is ,it's encrusting,laminar,and probably biogenic

edit,

and a nifty find,as well

Edited June 4, 2016 by doushantuo

[Anitafranklin]

There are well documented reefs in this area and some contain these algal mounds. Most of the area is Devoian rock but this area next to the lake bed has been cut into by streams and exposed some Ordovician strata. I also found these round smooth fossils in the same area - not sure what they are.