Thursday, October 6, 2011

Of Cephalopods and Sponges

Early Ordovician orthoconic nautiloids in a sponge/algal deposit, back when life was just beginning to diversify.

 

Early Triassic ammonoids in a sponge/microbial deposit, back when life was beginning to re-diversify.  Just after the Permian-Triassic mass extinction.