The Blair 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.
Blair’s center stands about 910 ft above sea level. Within three miles the land runs from 820 ft to 1,110 ft, a difference of 290 ft: rolling country. The highest named summit within 15 miles is Square Bluff, about 1,300 ft, 2 miles west-southwest.
Under the town center the state geologic map shows Cambrian, undivided (sandstone), from the Cambrian, 487 to 542 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 36×. 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. Age: Cambrian, 487 to 542 million years old. About 22 mi of the line.
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.
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 Blair reaches the Gulf of America by way of the Trempealeau and the Mississippi: about 1,750 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Blair; river miles along the main stem, rounded.