The Stonington 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.
Stonington’s center stands about 60 ft above sea level. Within three miles the land runs from 0 ft to 160 ft, a difference of 160 ft: gently rolling country. Open water lies within three miles. The highest named summit within 15 miles is Mount Chaplain, about 550 ft, 7 miles south-southeast.
Under the town center the state geologic map shows Devonian granite, from the Devonian, 359 to 422 million years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 43×. 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 5 mi of the line.
Mudstone, sandstone, siltstone. Age: Neoproterozoic, 542 to 1,000 million years old. About 3 mi of the line.
Granite. Age: Devonian, 359 to 422 million years old. About 2 mi of the line.
Granite. Age: Devonian, 359 to 422 million years old. About 1 mi of the line.
Felsic-volcanic, mafic-volcanic. Age: Middle Cambrian, 499 to 507 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.
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.