Indiana Highway 37 Roadcut geodes

Hwy-37 Roadcut Geode Hunt
Monroe County, Indiana
May 18, 2007
By Everett Harrington
(jesus_everett@hotmail.com)

On my way to Corydon I decide to stop in Bedford for a night to be able to collect geodes at the Harrodsburg Highway 37 cuts through a hill just north of the Monroe Reservoir exit This road cut exposes a zone of the Harrodsburg formation. The road cut, the entire formation, is very rich in mineralized geodes. The geodes are believed to be the precipitation of a migration of fluids which seeped into the basin during the Lower Mississipian Period, although we can only speculate as to their true origin. The cut has three benches and is thus quite high and hard to miss. Mike Streeter, Jay Loch and myself have hunting this location before and you can find Field Trip Reports at these following links;

December 2003 Field Trip Report
February 2004 Field Trip Report
October 2005 Field Trip Report

Both the north bound and south bound lanes are collectable, but parking is probably easiest on the south bound side.

When the overpass at the Harrodsburg exit was repaired the emergency shoulder on the north bound side was converted into a lead-on lane for north bound traffic. Parking on this side may be a problem but the change has not effected having enough room to collect. Peeling away the fractured limestone reveals geodes in the walls. Many areas at this locale are badly under cut and appear quite treacherous. Please use caution when collecting under any overhang. Good specimens can also be found by surveying the surface for geode halves that were lost by previous collectors. Note that the largest geodes are not always the most mineral rich. The lowest bench of the road cut contains nice calcite, quartz crystals, imbedded and free crystal barite and imbedded sphalerite crystals. You can typically find larger calcites and quartz geodes which sometime bear sprays of green millerite fibers on the second bench of the cut. There is little variance in the mineralization of the north and south bound cuts. If you find something on one side, it can probably be found on the other side as well because the same layers are present. Collecting is very easy; geodes will not be hard to find at the cut.