About the map: Several multi-state parks are outlined in red on the map; red paths indicate some of the more linear parks, such as parkways and rivers, but each will still have a "pin" identifier.

About the data: The primary information provided for each park includes (1) the geologic age/ages of rocks within park boundaries that have yielded fossils and (2) the types of fossils that have been found within those rocks.

Be aware that for each park, geologic ages are given only if fossils have been found in rocks of those ages. For example, let's say fossil mollusks have been found in Devonian rocks outside a particular park and it's known that those Devonian rocks are represented within the park — unless fossil mollusks have been found in those rocks within the park, then the Devonian is not mentioned.

Not all parks contain fossiliferous rocks, but they may (1) have fossils in their collections, (2) have fossils found in rocks used in construction, or (3) have fossils that were recovered in archeological investigations. If this is the case for a park, it will be so noted.

In most cases, fossil types are pluralized — e.g., mammoths — however, this simply means that the type is represented — perhaps a single mammoth tooth was found. It does not necessarily mean that the remains of multiple mammoths have been recovered within a park.

The sediments that make up some fossiliferous rock formations may have been deposited over two or more geologic ages. For the sake of simplicity, we assign fossils from multiple-age formations to a single age, but indicate what other age or ages the fossils might be. For example, if you see something like this for a park's Oligocene fossils: "[may be Miocene …] stromatolites, algal limestone," it means that the fossils listed following the bracketed text may be either Oligocene or Miocene.

Generally, the word "possible" — as used in, for example, "possible mastodon bones" — means that fossils have definitely been found in the park but that there is some doubt about the identification of those fossils. The word "possibly" (often appearing in italics) means that there is some question as to whether certain fossils were found within park boundaries or just outside them.