The ridge is associated with the seismically active Humboldt Fault zone.
It is also associated with the Proterozoic Midcontinent Rift System, which extends into northern Kansas about fifty miles west of the Nemaha.
This article about a specific United States geological feature is a stub.
You can help Wikipedia by expanding it.This Kansas state location article is a stub.
You can help Wikipedia by expanding it.This Oklahoma state location article is a stub.