The The Rock 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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The Rock’s center stands about 810 ft above sea level. Within three miles the land runs from 680 ft to 850 ft, a difference of 170 ft: gently rolling country. The highest named summit within 15 miles is Dorster Mountain, about 1,280 ft, 11 miles west.
Under the town center the state geologic map shows Granitic Gneiss undifferentiated, from the Precambrian to Paleozoic.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 28×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Gneiss. Age: Precambrian to Paleozoic. About 12 mi of the line.
Gneiss, mica-schist, amphibolite. Age: Precambrian to Paleozoic. About 6 mi of the line.
Age: Precambrian to Paleozoic. About 3 mi of the line.
Mica-schist. Age: Precambrian to Paleozoic. About 2 mi of the line.
Mylonite. Age: Precambrian to Paleozoic. About 0.4 mi of the line.
Schist. Age: Precambrian to Paleozoic. About 0.3 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 The Rock reaches the Gulf of America by way of Sullivan Creek, Tobler Creek, Swift Creek, the Flint and the Apalachicola: about 370 river miles.
240 miles of the trip are on the Flint.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of The Rock; river miles along the main stem, rounded.
