Here is a another Halysites segment from the Silurian Period. The chain appearance is much more apparent in this specimen. It could use som...

Besides finding Halysites in the Silurian layer I also come across segments of a species of horn coral that was huge. This is a smaller seg...

Here is an index fossil for the Silurian Period called a Halysites It was found in central Jefferson County in the state of Kentucky.