The Troy 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
Mostly cloudy
Partly cloudy
Partly cloudy
Troy’s center stands about 680 ft above sea level. Within three miles the land runs from 580 ft to 820 ft, a difference of 240 ft: 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 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 51×. 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: Late Cretaceous, 66 to 72 million years old. About 8 mi of the line.
Marlstone, chalk. Age: Late Cretaceous, 66 to 100 million years old. About 7 mi of the line.
Claystone, limestone. Age: Early Cretaceous, 100 to 145 million years old. About 6 mi of the line.
Black-shale, sand. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Limestone. Age: Late Cretaceous, 66 to 100 million 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 Troy reaches the Gulf of America by way of Pecan Creek, Big Elm Creek, the Little River and the Brazos: about 390 river miles.
320 miles of the trip are on the Brazos.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Troy; river miles along the main stem, rounded.
