Searching through horn corals I have collected in 2009 I search for Bordenia knappi. Instead I continue to identify Heliophyllum sp. horn coral fossils. Here are some images of 4 more that seemed picture worthy.
These horn coral fossils were found Jeffersonville or Beechwood Limestone of Clark County, Indiana. They existed in the Devonian Period.
Here is a budding horn coral emerging from a parent horn coral.