The Grandin 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.
Grandin’s center stands about 590 ft above sea level. Within three miles the land runs from 520 ft to 810 ft, a difference of 290 ft: rolling country. The highest named summit within 15 miles is Fuse Hill, about 780 ft, 11 miles southwest.
Under the town center the state geologic map shows Roubidoux Formation (sandstone, chert), from the Early Ordovician, 471 to 487 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 34×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, chert. Age: Early Ordovician, 471 to 487 million years old. About 19 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 5 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 Grandin reaches the Gulf of America by way of the Middle Fork North Prong Little Black, the North Prong Little Black, the Little Black, the Current, the Black River, the White River and the Mississippi: about 1,070 river miles.
620 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Grandin; river miles along the main stem, rounded.