Natural Bridge or an Arch?

Is it an arch or a natural bridge?

As many of you are aware we talk a lot about arches in this group, but we have never really discussed the difference between a natural arch and a natural bridge.  A little bit of confusion is thrown in because of what Natural Bridge and Sky Bridge are named in the Red River Gorge.  When we are saying there are now 2,500 documented arches in the Arch Database we are including natural bridges in that number. Technically a natural bridge is still an arch.  In most cases an arch is formed by wind and rain or also called weathering.  There are some fracture type arches which are associated with geological movement.  A Natural Bridge is formed by running water.  That water doesn’t necessarily have to be constantly flowing either. The most well known true natural bridge in the state is Rock Bridge in the Red River Gorge which also happens to be the best example. Where some confusion comes in are in the cases of Natural Bridge Arch and Sky Bridge Arch.  Often when folks are joining the group and they answer the participation question “What is your favorite arch?” they will respond with “It’s not an arch but a Natural Bridge.”  Truth is Natural Bridge is an arch. The reason for this anomaly is that Natural and Sky Bridges were both named prior to the modern standard of classification.  Both are shelter type arches.

Below are examples of a natural bridge and an arch.

Rock Bridge:

© Christopher Morris


Natural Arch:

© Bill Fultz