The Island Falls 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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Island Falls’s center stands about 510 ft above sea level. Within three miles the land runs from 430 ft to 940 ft, a difference of 510 ft: hilly country. The highest named summit within 15 miles is Pickett Mountain, about 1,720 ft, 15 miles northwest.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 26×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granite. Age: Devonian, 359 to 422 million years old. About 9 mi of the line.
Quartzite, calc-silicate-rock. Age: Silurian to Devonian, 359 to 445 million years old. About 7 mi of the line.
Slate, sandstone. Age: Silurian, 422 to 445 million years old. About 6 mi of the line.
Slate, siltstone, quartzite. Age: Silurian, 425 to 445 million years old. About 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 Island Falls reaches the Atlantic Ocean by way of the West Branch Mattawamkeag, the Mattawamkeag and the Penobscot: about 150 river miles.
Lake on the way: Upper Mattawamkeag Lake.
85 miles of the trip are on the Penobscot.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Island Falls; river miles along the main stem, rounded.
