ABSTRACT
The Balcones Escarpment is the discontinuous topographic expression of displacement across the Balcones Fault Zone. Besides its separating the limestone uplands to the west from chalk and claystone prairies to the east, dramatic changes also are seen for soils and vegetation and animal habitats; weather and climate; surface water regimes, and groundwater reservoirs. In short, this break marks the beginning of the American West in an ecologic context, but the sum of natural changes have had (and continue to impose) profound impacts on human institutions.