The Harrison 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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Harrison’s center stands about 1,710 ft above sea level. Within three miles the land runs from 1,190 ft to 2,370 ft, a difference of 1,180 ft: steep hill country. The highest named summit within 15 miles is Martin Hill, about 2,790 ft, 8 miles south-southeast.
The section below crosses 17 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 10×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Siltstone. Age: Late Devonian, 359 to 384 million years old. About 5 mi of the line.
Shale. Age: Ordovician, 445 to 487 million years old. About 4 mi of the line.
Siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 4 mi of the line.
Sandstone, conglomerate. Age: Carboniferous, 299 to 324 million years old. About 2 mi of the line.
Age: Early Devonian to Middle Devonian, 384 to 422 million years old. About 2 mi of the line.
Sandstone. Age: Late Devonian, 359 to 384 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 11 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 Harrison reaches Chesapeake Bay and the Atlantic Ocean by way of the Raystown Branch Juniata, the Juniata and the Susquehanna: about 280 river miles.
Lakes on the way: Lake Aldred and Raystown Lake.
90 miles of the trip are on the Juniata.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Harrison; river miles along the main stem, rounded.
