The Hillsboro 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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Hillsboro’s center stands about 770 ft above sea level. Within three miles the land runs from 560 ft to 850 ft, a difference of 290 ft: rolling country. The highest named summit within 15 miles is Vinegar Hill, about 1,070 ft, 15 miles south.
Under the town center the state geologic map shows Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (dolostone), from the Early Ordovician, 471 to 487 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 40×. 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. Age: Early Ordovician, 471 to 487 million years old. About 14 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 5 mi of the line.
Dolostone, sandstone, limestone. Age: Early Ordovician to Middle Ordovician, 459 to 487 million years old. About 2 mi of the line.
Sandstone, chert. Age: Early Ordovician, 471 to 487 million years old. About 1 mi of the line.
Sandstone, limestone, dolostone. Age: Middle Ordovician to Late Ordovician, 454 to 468 million years old. About 1 mi of the line.
Clay, silt, sand. Age: Holocene, less than 12,000 years old. About 0.6 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 Hillsboro reaches the Gulf of America by way of Belews Creek, the Big River, the Meramec and the Mississippi: about 1,200 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Hillsboro; river miles along the main stem, rounded.
