This is a fine example of Devonian (approx. 350 - 400,000,000 years ago) fossil hash. This plate was recovered near Bardstown Kentucky (Shelby County) from Laurel Dolomite formations. This plate contains a rich mixure of invertebrates, crinoids, and even trilobites.
Refer to the photos. The brass centimeter cube is shown for scale and is not included. You are purchasing the hash plate shown. It measures approx. 7 x 5 x .5 inches. Your purchase will include an ID label. Note, the arrow in the photo shows the location of one trilobite in the matrix, there are many other fossils that could be revealed with further preparation. There are already some crinoid stems showing as well.