The Thomaston 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.
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Thomaston’s center stands about 200 ft above sea level. Within three miles the land runs from 130 ft to 270 ft, a difference of 140 ft: gently rolling country.
Under the town center the state geologic map shows Midway Group; Clayton Formation (limestone), from the Paleocene, 56 to 66 million years old.
The section below crosses 6 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.
Clay, sand. Age: Paleocene, 56 to 66 million years old. About 9 mi of the line.
Sand, clay, sandstone. Age: Cretaceous, 66 to 145 million years old. About 6 mi of the line.
Chalk. Age: Cretaceous, 66 to 145 million years old. About 4 mi of the line.
Sand, clay. Age: Paleocene, 56 to 66 million years old. About 2 mi of the line.
Sand. Age: Holocene, less than 12,000 years old. About 2 mi of the line.
Limestone. Age: Paleocene, 56 to 66 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 Thomaston reaches Mobile Bay and the Gulf of America by way of Michigan Creek, the Chickasaw Bogue, the Tombigbee and the Mobile: about 220 river miles.
140 miles of the trip are on the Tombigbee.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Thomaston; river miles along the main stem, rounded.
