Irregular Natural Arch

Examples: Woodpecker Rock, Keystone Bridge, Buffalo Rock, unnamed arch

Any natural arch that cannot be placed in the taxonomy in any of the other types is considered to be an irregular natural arch. The combination of attributes these natural arches exhibit is unusual, even unique. It may be possible to determine how an irregular natural arch formed from its observable attributes, but if so, either none of the standard formation modes are involved or there has been an unusual combination of them. A maturity attribute cannot be assigned to this type of natural arch.