This coprolite was collected by a school in South Dakota. It lacked provenance/identification so it was dumped along with other fossils/minerals in an area where the public could dig through the rock pile and take what they like. When additional stones were dropped on top of this one, it broke open revealing a dark, crumbly interior. Coprolites from the nearby Lance and Hell Creek Formations can have a similar appearance, so it was collected. Microscopic examination confirmed the dark interior was comprised of partially digested bone. Without knowing the exact location from which this coprolite originated, it is difficult to know how old this specimen is. However, due to similarity of the coprolites to those that can be found in nearby That said, coprolites of this type can be found nearby in the nearby Hell Creek and Lance Formations, both of which date to the uppermost Cretaceous Period. For this reason, I feel confident that this is fossil poo that was likely first dumped by a dinosaur in the vicinity of western South Dakota some 65 million years ago.
This is an example of why it is so important to know the location and geologic formation where fossils are discovered. To the untrained eye, there is nothing extraordinary about a rock such as this. Most people would not even stoop down to pick it up.