- Nov 19, 2002
I found these fossils in the lower Fillmore Formation (Stairsian Stage, Ibexian Series, Ordovician System...about 490mya). This would be about the time of the first great expansion of the Nautiloids. I believe they are the fossilized siphuncular deposits of endocerids called endocones. I havent been able to see any trace of septa or camera so I am not completely sure.