The Crawford Upland of

Southern Indiana Southern Indiana is a region consisting of the southern third of the state of Indiana. The region's history and geography has led to a blend of Northern and Southern culture distinct from the remainder of Indiana. It is often considered to be p ...

, United States. The eastern section of the

Indiana Uplands The Indiana Uplands or the Hoosier Uplands are a geographical region in south-central Indiana. On a topographical map the Indiana Uplands begin slightly north of the city of Martinsville, Indiana and continue south to the Ohio River. The descripti ...

, this region contains the hilliest terrain in the state caused by the outcropping of

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

units at the surface. In some areas erosion cuts through the sandstone layers completely and exposes underlying

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s. The exposure of limestone at the surface in the Crawford Upland results in the formation of

caves A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

, dolines, and other surface expressions of

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

topography. The alternating sandstones, limestones, and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

of the West Baden and Stephensport

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

s that compose the Crawford Upland are Mississippian in age.Lakey, B., Krothe, N.C. (1996). Stable isotopic variation of storm discharge from a perennial karst spring, Indiana. ''Water Resources Research'' 32(3), 721-731

Interstate 64 Interstate 64 (I-64) is an east–west Interstate Highway in the Eastern United States. Its western terminus is at I-70, U.S. Route 40 (US 40), and US 61 in Wentzville, Missouri. Its eastern terminus is at an interchange w ...

traverses this section within Perry, Crawford, Harrison, and Floyd Counties.

References

Karst plateaus Landforms of Indiana Geologic formations of Indiana Mississippian United States {{US-geology-stub