1) Burgess Shale fossil
Found on
https://www.crosswordclues.com/clue/sphenothallus
Sphenothallus is a problematic extinct genus lately attributed to the conulariids. It was widespread in shallow marine environments during the Paleozoic. == Occurrence == Sphenothallus is represented in the Cambrian period in the Kaili biota and the Mount Stephen trilobite beds, where it co-occurs with the similar organisms Cambrorhythium and Byro...
Found on
http://en.wikipedia.org/wiki/Sphenothallus
No exact match found.
