Agate Bridge
Spanning a gully like a bridge, Agate Bridge is in fact a large petrified log.
Guide Sections
Use Agate Bridge's guide sections to understand how this stop fits into the larger park plan.
Agate Bridge Details
Difficulty
Low
Distance
N/A
Estimated time
N/A
Region
N/A
Spanning a gully like a bridge, Agate Bridge is in fact a large petrified log. When numerous trees washed into this floodplain 225 million years ago, buried by silt, mud and volcanic ash, the sediment cut off the oxygen supply to the trees and slowed their decay. Silica from the groundwater seeped into the logs and eventually replaced the original wood tissue with the quartz we see today in specimens such as Agate Bridge. Centuries of floodwaters created the arroyo beneath this 110-foot log, turning it into a natural bridge. In 1917, a concrete span was constructed under the bridge to support it. Agate Bridge is just a short walk from a parking area.