Cavern

(Morphologic type)

Examples: Natural Bridge of New York, unnamed arch

A cavern is a large subterranean cavity. Almost all caverns with two or more entrances technically qualify as natural arches. They are included in the taxonomy as a morphologic type even though it is usually easy to determine how any given cavern formed. The attribute that distinguishes a cavern from other natural arches is a morphologic attribute. Light entering the opening, including diffused and reflected light, does not reach all parts of it, i.e., an observer can be positioned in the opening such that they are in total darkness during broad daylight. Using the standard attribute list, a cavern is a natural arch that has the morphologic attribute of being cavernous.

Caverns can form in many different ways. As stated above, the geologic processes that contributed to the formation of any given cavern are usually obvious. However, about the only caverns that have much interest as natural arches are waterfall natural bridges with cavernous subterranean passageways. Upon occasion, some of these have been labeled by the public as natural tunnels or even natural bridges. Even though it is clear that these features formed exactly like non-cavernous waterfall natural bridges, they are included in the taxonomy as caverns. Indeed, any natural arch that is cavernous is considered a cavern regardless of how it formed.

The taxonomy does not assign maturity attributes to caverns.