The Schielenberg roof slate pit in the Breitenthal district near Herrstein is the site of several dozen different fossils. mineralienatlas.de/?l=57751
The slope is criss-crossed by several farm roads that lead to the tunnels above the huge slate rubble heaps. Most are fenced off as bat roosts, but some are also accessible.
The rubble heap must not and should not be entered, as the loose layering tends to quickly fall off and everything ends up directly on the street! So stay on the economic routes.