The Silo 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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Chance of showers; warmer
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Silo’s center stands about 800 ft above sea level. Within three miles the land runs from 680 ft to 870 ft, a difference of 190 ft: gently rolling country.
Under the town center the state geologic map shows Dexter Member of Woodbine Formation (sandstone, shale), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 5 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.
Claystone. Age: Early Cretaceous, 100 to 145 million years old. About 7 mi of the line.
Sandstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 6 mi of the line.
Fine-detrital. Age: Holocene, less than 12,000 years old. About 5 mi of the line.
Marlstone. Age: Early Cretaceous, 100 to 145 million years old. About 3 mi of the line.
Limestone, shale, marlstone. Age: Early Cretaceous, 100 to 145 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 Silo reaches the Gulf of America by way of Newberry Creek, the Washita, the Red River, the Atchafalaya and the Lower Atchafalaya: about 840 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 Silo; river miles along the main stem, rounded.
