The Mount Holly 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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70° on Nov. 11, 2020, the hottest reading for this week of the year since 1940. Next is 65° in 2022.
Mount Holly’s center stands about 1,570 ft above sea level. Within three miles the land runs from 1,190 ft to 2,110 ft, a difference of 920 ft: steep hill country. The highest named summit within 15 miles is Killington Peak, about 4,190 ft, 11 miles north.
The section below crosses 17 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 8×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Gneiss. Age: Mesoproterozoic, 1.2 to 1.6 billion years old. About 5 mi of the line.
Paragneiss, quartz-feldspar-schist. Age: Mesoproterozoic, 1.2 to 1.4 billion years old. About 4 mi of the line.
Phyllite, muscovite-schist. Age: Neoproterozoic to Cambrian, 487 to 1,000 million years old. About 2 mi of the line.
Paragneiss, leucocratic-granitic. Age: Mesoproterozoic, 1.3 to 1.3 billion years old. About 2 mi of the line.
Dolostone. Age: Early Cambrian, 521 to 542 million years old. About 2 mi of the line.
Dolostone, phyllite. Age: Middle Cambrian, 497 to 521 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. 11 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.
Mount Holly straddles the St. Lawrence Divide. Rain on the east side runs to Long Island Sound and the Atlantic Ocean; most of the rest goes to the St. Lawrence River.
From the center of town, a raindrop reaches the St. Lawrence River by way of the Mill, Otter Creek and the Richelieu: about 240 river miles. The St. Lawrence carries it on to the Atlantic. One that lands on the east side reaches Long Island Sound and the Atlantic Ocean by way of Branch Brook, the Black River and the Connecticut: about 220 river miles.
Lake on the way: Lake Champlain.
100 miles of the trip are on Otter Creek.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mount Holly; river miles along the main stem, rounded.
Mount Holly has a warm-summer humid continental climate. Summer afternoons average 75° in July; winter nights fall to about 8° in January. About 51 inches of rain fall in a normal year.
Normals 1991–2020 and records since 1940 at Peru, 14 miles south-southwest, 130 ft higher. NOAA, through RCC-ACIS.
