Spotted a small black speck while trimming down mineral specimens with the diamond saw. Later took some pictures through the stereo microscope using 23x and 40x magnification. The matrix is very fragile but this appears to be a scolecodont without the serrated edge. Found in Waldron Shale (Middle Silurian) of Clark County, Indiana.
In addition, here is an interesting specimen of iridescent pyrite also found in the Waldron Shale.
This next image is a microscope shot of a Waldron Shale pyrite ball.
Last picture is not from the Silurian period but much older. It dates to the Ordovician Period and might be Drake Formation. Found east of Louisville, Kentucky.