How Was the Natural Bridge Formed?
Posted by: 
Volcanoguy
N 42° 53.314 W 122° 27.888
10T E 543702 N 4748579
Sign in the interpretive kiosk at trailhead to Natural Bridge.
Waymark Code: WM7R1A
Location: Oregon, United States
Date Posted: 11/24/2009
Views: 3
Marker Name: How Was the Natural Bridge Formed?
Marker Text: It began as a River of Fire . . . when basaltic lava flowed from fissures in the earth’s surface and traveled long distances through lava tubes.
Lava tubes develop when the upper surface of a basalt flow rapidly cools, causing the outer edges to solidify while the hot inner lava continues to flow underneath. As the molten lava drains out, it leaves behind a long hollow tube.
Eventually, the river of fire was replaced by a River of Water. The Rogue River entered a section of a lava tube, becoming a “hidden river” which flows below ground for 200 feet. In doing so it created a natural bridge that connects the banks of the river.
Indians and early settlers used this natural bridge to cross the Rogue RIver.
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