Ibexian Series, Stairsian Stage
Zone D Cephalopods


These cephalopods were found in the lower member of the Fillmore Formation in an algal-sponge reef deposit.  The cephalopods were deposited in the reef, then the reef was scalloped, exposing the cephalopods, then a hardground (?algal-bacterial mat) formed (the dark orange brown rind). No sign of the siphuncle is seen on most of the Orthocone specimens, so positive identification cannot be determined at this time, but they are probably Endocerids.


Aphetoceras

Aphetoceras,  a loose coiled Tarphycerid


Aphet2
another Aphetoceras showing the siphuncle and septa



Portion of a sponge algal reef showing a couple of unidentified Orthocones.

reef



Endocerid

An Endocerid?

zondo2

An Orthocone showing the body chamber and part of the phragmocone


ZoneD ortho  
an Orthocone with closely spaced septa


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