The Bridgewater 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.
Bridgewater’s center stands about 990 ft above sea level. Within three miles the land runs from 920 ft to 1,130 ft, a difference of 210 ft: rolling country.
Under the town center the state geologic map shows Lower Ordovician (dolostone, sandstone), from the Early Ordovician, 471 to 487 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 56×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 14 mi of the line.
Shale, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 10 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 0.2 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 Bridgewater reaches the Gulf of America by way of the Cannon and the Mississippi: about 1,820 river miles.
Lake on the way: Lake Pepin.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Bridgewater; river miles along the main stem, rounded.