The Collinsville 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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15° on Nov. 15, 1969, the coldest reading for this week of the year since 1949. Next is 16° in 2019.
Collinsville’s center stands about 720 ft above sea level. Within three miles the land runs from 670 ft to 1,370 ft, a difference of 700 ft: hilly country. The highest named summit within 15 miles is Mount Brandon, about 1,690 ft, 10 miles northeast.
Under the town center the state geologic map shows Monteagle Limestone (limestone, dolostone, shale), from the Carboniferous, 324 to 359 million years old.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 17×. 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, conglomerate. Age: Carboniferous, 299 to 324 million years old. About 12 mi of the line.
Dolostone, limestone. Age: Cambrian to Ordovician, 445 to 542 million years old. About 3 mi of the line.
Sand. Age: Pleistocene, less than 2.6 million years old. About 1 mi of the line.
Limestone. Age: Ordovician, 445 to 487 million years old. About 1 mi of the line.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 1 mi of the line.
Dolostone, limestone. Age: Cambrian to Ordovician, 445 to 542 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. 6 smaller units 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 Collinsville reaches Mobile Bay and the Gulf of America by way of Little Wills Creek, Big Wills Creek, the Coosa, the Alabama and the Mobile: about 580 river miles.
Lake on the way: Lay Lake.
310 miles of the trip are on the Alabama.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Collinsville; river miles along the main stem, rounded.
Collinsville has a humid subtropical climate. Summer afternoons average 88° in July; winter nights fall to about 30° in January. About 57 inches of rain fall in a normal year, with about 1 inch of snow.
On November 14 Collinsville normally reaches 61° and falls to 39°. The record high is 82°, in 1955; the record low 19°, in 2019. The most rain on this date, 2.68 in, fell in 1957.
Normals 1991–2020 and records since 1949 at Sand Mount Substation, 6 miles west-northwest, 470 ft higher. NOAA, through RCC-ACIS.
