The Ardmore 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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Ardmore’s center stands about 3,560 ft above sea level. Within three miles the land runs from 3,500 ft to 3,740 ft, a difference of 240 ft: rolling country. The highest named summit within 15 miles is Roundtop, about 4,520 ft, 14 miles south-southeast.
Under the town center the state geologic map shows Alluvium (coarse-detrital, fine-detrital), from the Quaternary, less than 2.6 million years old.
The section below crosses 8 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 37×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 9 mi of the line.
Coarse-detrital, fine-detrital. Age: Quaternary, less than 2.6 million years old. About 8 mi of the line.
Clay. Age: Early Oligocene to Late Oligocene, 23 to 34 million years old. About 2 mi of the line.
Black-shale. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Shale, siltstone. Age: Early Cretaceous, 100 to 145 million years old. About 1 mi of the line.
Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 0.7 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 2 smaller units along the line are not listed.
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 Ardmore reaches the Gulf of America by way of Hat Creek, the Cheyenne, the Missouri and the Mississippi: about 2,590 river miles.
Lakes on the way: Lake Oahe, Lake Sharpe, Lake Francis Case and Lewis and Clark Lake.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Ardmore; river miles along the main stem, rounded.
