The Greenfield 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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14° on Nov. 16, 1933, the coldest reading for this week of the year since 1873. Next is 15° in 1959.
Greenfield’s center stands about 1,500 ft above sea level. Within three miles the land runs from 1,300 ft to 1,550 ft, a difference of 250 ft: rolling country.
Under the town center the state geologic map shows Venango Formation (siltstone, conglomerate), from the Late Devonian, 359 to 384 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 15×. 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. Age: Late Devonian, 359 to 384 million years old. About 6 mi of the line.
Siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 5 mi of the line.
Siltstone, conglomerate. Age: Late Devonian, 359 to 384 million years old. About 5 mi of the line.
Shale. Age: Late Devonian, 359 to 384 million years old. About 3 mi of the line.
Siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 0.9 mi of the line.
Shale, sandstone. Age: Late Devonian, 359 to 384 million years old. About 0.6 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.
Greenfield straddles the St. Lawrence Divide. Rain on the north side runs to Lake Erie; most of the rest goes to the Gulf of America.
From the center of town, a raindrop reaches the Gulf of America by way of West Branch French Creek, French Creek, the Allegheny, the Ohio and the Mississippi: about 2,170 river miles. One that lands on the north side reaches Lake Erie by way of Twelvemile Creek: about 4 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
970 miles of the trip are on the Ohio.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Greenfield; river miles along the main stem, rounded.
Greenfield has a hot-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 21° in January. A normal year brings about 104 inches of snow; with the rain, that comes to about 43 inches of water.
On November 14 Greenfield normally reaches 51° and falls to 37°. The record high is 73°, in 1994; the record low 18°, in 1905. The most rain on this date, 1.27 in, fell in 2011.
Normals 1991–2020 and records since 1873 from the Erie Area threaded record (Erie International Airport, 18 miles west, 770 ft lower). NOAA, through RCC-ACIS.
