The Sulphur 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.
Sulphur’s center stands about 1,000 ft above sea level. Within three miles the land runs from 920 ft to 1,210 ft, a difference of 290 ft: rolling country.
Under the town center the state geologic map shows Woodford Shale (black-shale), from the Late Devonian, 359 to 384 million years old.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 35×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Black-shale. Age: Late Devonian, 359 to 384 million years old. About 5 mi of the line.
Shale, limestone, sandstone. Age: Carboniferous, 299 to 324 million years old. About 5 mi of the line.
Coarse-detrital, fine-detrital. Age: Pleistocene, less than 2.6 million years old. About 4 mi of the line.
Shale, sandstone, limestone. Age: Carboniferous, 299 to 324 million years old. About 3 mi of the line.
Fine-detrital. Age: Holocene, less than 12,000 years old. About 2 mi of the line.
Limestone, conglomerate, dolostone. Age: Early Ordovician, 471 to 487 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 5 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 Sulphur reaches the Gulf of America by way of Rock Creek, the Washita, the Red River, the Atchafalaya and the Lower Atchafalaya: about 920 river miles.
680 miles of the trip are on the Red River.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sulphur; river miles along the main stem, rounded.