The Douglas 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.
Douglas’s center stands about 260 ft above sea level. Within three miles the land runs from 190 ft to 290 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Neogene undifferentiated (sandstone, claystone), from the Tertiary Neogene, 2.6 to 23 million years old.
The section below crosses 2 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.
Sandstone, claystone. Age: Tertiary Neogene, 2.6 to 23 million years old. About 20 mi of the line.
Fine-detrital. Age: Quaternary, less than 2.6 million years old. About 4 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 Douglas reaches the Atlantic Ocean by way of Twenty Mile Creek, the Seventeen Mile and the Satilla: about 210 river miles.
170 miles of the trip are on the Satilla.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Douglas; river miles along the main stem, rounded.