Primary Sedimentary Structures in Helena Formation Limestone

[@sidneysentell2510]

Thank you Professor. Another excellent presentation from GNP.

[@PlayNowWorkLater]

I was just learning about these (stromatolites) the other day. So cool to see some actual examples. They are from before the Cambrian explosion aren’t they?

[@callanbentley]

@@PlayNowWorkLater These ones are, yes.