The Westminster 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.
Westminster’s center stands about 710 ft above sea level. Within three miles the land runs from 570 ft to 720 ft, a difference of 150 ft: gently rolling country.
Under the town center the state geologic map shows Austin Chalk (marlstone, chalk), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 60×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Marlstone, chalk. Age: Late Cretaceous, 66 to 100 million years old. About 15 mi of the line.
Claystone. Age: Late Cretaceous, 66 to 72 million years old. About 7 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 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.
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 Westminster reaches Galveston Bay and the Gulf of America by way of Elm Grove Creek, Sister Grove Creek, the East Fork Trinity and the Trinity: about 490 river miles.
Lakes on the way: Woodlands Golf Course Lake, Lavon Lake and Corder Lake.
220 miles of the trip are on the Trinity.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Westminster; river miles along the main stem, rounded.