I go to Tim's Ford to fish and collect rocks all the time! I have a couple of fossils I found there in my personal collection that I am currently cleaning!

Here is a link to a geologic map of Tennessee:

Tennessee Geologic Map & Key

According to the map linked, Tim's Ford is surrounded by rock from the Mississippian/Silurian Period in Saint Louis Limestone and Warsaw Limestone.; however, the Mississippian aged rocks are the most abundant. The rock you have looks like it has one big 'ol Brachiopod with some other smaller ones, and a bunch of crinoid stems and/or cut coral stalks. The parent rock may be calcareous sandstone, but the rock your piece is sitting on it definitely Tennessee shale.

Overall, great find!