The Decatur 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.
Chance of showers
Showers likely
Partly cloudy
Sunny; warmer
Partly cloudy
Chance of showers
Partly cloudy
Decatur’s center stands about 1,100 ft above sea level. Within three miles the land runs from 830 ft to 1,080 ft, a difference of 250 ft: rolling country.
Under the town center the state geologic map shows Goodland Limestone and Walnut Clay, undivided, from the Early Cretaceous, 100 to 113 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 45×. 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: Early Cretaceous, 100 to 145 million years old. About 9 mi of the line.
Sandstone. Age: Early Cretaceous, 100 to 145 million years old. About 9 mi of the line.
Limestone. Age: Early Cretaceous, 100 to 113 million years old. About 4 mi of the line.
Limestone, marlstone. Age: Early Cretaceous, 100 to 145 million years old. About 1 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 years old. About 0.8 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 Decatur reaches Galveston Bay and the Gulf of America by way of Martin Branch, the West Fork Trinity and the Trinity: about 570 river miles.
Lakes on the way: Woodlands Golf Course Lake, Eagle Mountain Lake and Lake Worth.
270 miles of the trip are on the Trinity.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Decatur; river miles along the main stem, rounded.
