I've discussed the Halysites coral from the Lousiville limestone before in this post. Since then I've had the opportunity to collect some for myself.
These next two pictures show you a piece of limestone with the coral still preserved within. The straight parallel lines, representing a lateral section through the coral, heralding the presence of Halysites within.
Viewed end on you can see cross sections through the corallites.
It's very easy to find specimens that are replaced with "beekite" quartz and have weathered free of the limestone.
This is a view of the bottom of the above pictures piece. You can see some areas that a smooth and others that are open to the corallite. I believe the smooth areas are the base of the corallites where they contacted the mud surface. Not all of the bases are at the same level with each other This could be becasue the muddy bottom surface raised as the coral grew and budded out so that younger corallites would have set their "roots" in the sediment at the level it was when they started to grow.
This piece shows that the colonies could grow fairly tall.
One more small piece.
Thanks to Mike and Kenny for showing the spot to find these fossils!