The Unionville 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.
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Unionville’s center stands about 5,090 ft above sea level. Within three miles the land runs from 4,400 ft to 6,340 ft, a difference of 1,940 ft: steep hill country. The highest named summit within 15 miles is Three Brothers, about 8,530 ft, 14 miles southwest.
The section below crosses 8 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 5×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granitic. Age: Cretaceous, 66 to 145 million years old. About 11 mi of the line.
Age: Pleistocene to Holocene, less than 1.8 million years old. About 7 mi of the line.
Siltstone, sedimentary-breccia, conglomerate. Age: Early Eocene to Early Miocene, 16 to 56 million years old. About 2 mi of the line.
Limestone, dolostone, black-shale. Age: Early Mississippian to Middle Mississippian, 331 to 359 million years old. About 1 mi of the line.
Limestone, dolostone, shale. Age: Late Devonian to Early Mississippian, 347 to 374 million years old. About 1 mi of the line.
Age: Tertiary, 2.6 to 66 million years old. About 0.9 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 2 smaller units along the line are not listed.
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 Unionville reaches the Gulf of America by way of Tenmile Creek, Prickly Pear Creek, the Missouri and the Mississippi: about 3,410 river miles.
Lakes on the way: Lake Oahe, Lake Sakakawea, Lake Fort Peck and Lake Sharpe.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Unionville; river miles along the main stem, rounded.
