The Altamont 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.
Sunny
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy; cooler
Showers likely
Altamont’s center stands about 1,840 ft above sea level. Within three miles the land runs from 1,700 ft to 1,900 ft, a difference of 200 ft: gently rolling country. The highest named summit within 15 miles is Buffalo Hill, about 2,010 ft, 8 miles west-southwest.
Under the town center the state geologic map shows Carlile Shale, from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 23×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 12 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 11 mi of the line.
Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 2 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 Altamont reaches the Gulf of America by way of Caine Creek, the South Fork Yellow Bank, the Yellow Bank, the Minnesota and the Mississippi: about 2,200 river miles.
Lake on the way: Lake Pepin.
1,750 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Altamont; river miles along the main stem, rounded.
