The limestone sand here is supposed to be filled with fossils, mostly bryozoans and crinoids.  There are other types found here.  You can find more information from the website source:

http://www.nashvillefossils.com/fieldtrips/pluspark/pluspark.html

This is from the website's directions:

"The site is on the east side of Murfreesboro Pike between the interstate and Plus Park Blvd.  Park in the gas station parking lot and walk south toward the bus stop.  To get to this site you will have to climb down into the gully next to the road and then up a bit on to the exposure.  Because it is on a major street, the site has a good deal of broken glass.  It also is overgrown during the growing season and has cactus growing right where you want to lay your hand down. "