The geology of Terre Haute was most influenced by the last period of glaciation approximately 10,000 years ago. Receeding glaciers left jutting granite outcroppings and rock-strewn slopes that can still be seen today throughout the property. These glaciers also formed gravel beds which became the streams and aquifers of the region, further shaping the landscape.

Terre Haute (Bogus Mountain) forms a North-South ridge - one of the southernmost of these ridges that eventually form the "Litchfield Hills" and, further north, the Berkshire mountains of Massachusetts. Inactive "locked up" seismic fault lines parallel the ridge.

Did Bethel once touch Africa?
Some geologists have hypothesized that the hilly region of Northern Fairfield County may have originated when plates of the earth's crust separated, dividing the "supercontinent" of Pangaea into the familiar modern continents. It is believed that this region once connected the modern East Coast of North America to the Northwestern corner of North Africa (see map at right). This hypothesis is supported by known geological similarities between the two areas, and an increasing understanding of plate techtonics.