Geodes containing a large variety of minerals are to be found in a 15 foot thick chirty layer of limestone exposed by the roadcut along State Route 37, 10.5 miles north of Bedford. This collecting site is just south of the Monroe Lake exit.
Typical geode specimens contain quartz with either calcite, dolomite or barite.
Less common are geodes containing marcasite, millerite tufts and sprays, pyrite or sphalerite. Care should be exercised in obtaining and opening any specimens found embedded in massive limestone as these are most the likely to contain the delicate millerite. Other local outcrops in this area are reported to have yielded geodes containing ankerite, aragonite, goethite, siderite and honessite. Kentland is a small northwestern Indiana town in which exists the only dome structure in the state. There is a quarry, the Newton County Stone Quarry, which extracts the exposed stone for a variety of purposes.