The Mad River 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.
Mad River’s center stands about 2,590 ft above sea level. Within three miles the land runs from 2,450 ft to 5,500 ft, a difference of 3,050 ft: mountain country. The highest named summit within 15 miles is Blake Mountain, about 5,910 ft, 11 miles north-northwest.
Under the town center the state geologic map shows Franciscan Complex, unit 1 (Coast Ranges) (sandstone, mudstone), from the Jurassic to Cretaceous, 66 to 202 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 4×. 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, mudstone. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 13 mi of the line.
Melange. Age: Devonian to Jurassic, 145 to 422 million years old. About 5 mi of the line.
Mica-schist. Age: Early Cretaceous, 110 to 143 million years old. About 3 mi of the line.
Slate, graywacke. Age: Triassic to Late Jurassic, 145 to 252 million years old. About 1 mi of the line.
Greenstone. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 1 mi of the line.
Peridotite, serpentinite. Age: Neoproterozoic to Early Jurassic, 175 to 1,000 million years old. About 0.7 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 Mad River reaches the Pacific Ocean by way of the Mad: about 70 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mad River; river miles along the main stem, rounded.