Waldron Shale Dawsonoceras

One of my favorite cephalopods to find but an experience only encountered about once a year.  This fossil is mostly a mold but some the sinusoidal lines are still visible in the first picture.  Fossil is about 3 cm long and 1.2 cm wide.  It was odd that right before I found this fossil my thoughts were on why no cephalopods have been encountered in the shale with mostly brachiopod and crinoid fossils.

Dawsonoceras cephalopod found in the Waldron Shale of Clark County, Indiana.  Creature existed in the Middle Silurian Period.