Ibexian Series, Tulean Stage
Zone G-1 Cephalopods
were found near the top of the informal Slope-forming shaly siltstone
Member of the Fillmore
Formation in a nodular silty shale bed.
The internal molds of the living chamber of orthocones are the most
common fossil, most of the phragmocones were probably crushed and all
the shell material had been disolved prior to lithification of the
body chamber molds
some have burrows between where the shell was, and the mud infill.
Below are 3 views of an Ellesmerocerid? phragmocone from the same beds.
must have been partially damaged and filled with sediment prior to the
rest of it being crushed and the shell material dissolved.
This specimen seems to be an endogastric cyrtocone, but it may just be
a distorted orthocone.
end view showing
the large ventral siphuncle