The Olanta plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Olanta’s center stands about 120 ft above sea level. Within three miles the land runs from 100 ft to 160 ft, a difference of 60 ft: gently rolling country.
Under the town center the state geologic map shows Bear Bluff Formation (sand, limestone), from the Tertiary, 2.6 to 66 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand, limestone. Age: Tertiary, 2.6 to 66 million years old. About 17 mi of the line.
Limestone, sand. Age: Pleistocene, less than 2.6 million years old. About 6 mi of the line.
Sand, gravel. Age: Quaternary, less than 2.6 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Olanta reaches the Atlantic Ocean by way of Bushy Branch, Douglas Swamp, Pudding Swamp and the Black River: about 120 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Olanta; river miles along the main stem, rounded.