Very interesting bridge, and unique by its use of beautiful geodes in its construction. I noted a 1933 date marker in the bridge. This may be a bridge built through Depression relief programs. Many park bridges were built using these programs., and many of these bridges simulated stone arch bridges, but were not true stone arch bridges. This possibility as well as the construction date and general shape of the bridge lead me to believe this is not a stone arch, but is likely some type of concrete or steel bridge with stone facing. There is no way to tell from the existing photos; someone would have to look under the bridge to make a determination.