Pocono Plateau

Geology

The Pocono Plateau is the northern, glaciated portion of the Allegheny Plateau physiographic province. Its surface is held up by two erosion-resistant sandstone formations — the Pocono Formation (Mississippian, ~340 Ma) and the underlying Catskill / Pottsville sandstones — that resist weathering more stubbornly than the shales and limestones in the surrounding lowlands. The plateau therefore stands 1,000–1,500 feet above the Great Valley to its south and the Wyoming Valley to its west.

Elevations across the plateau run from ~1,500 ft on its southern slope to ~2,200 ft on the highest knobs (Camelback, Big Pocono).

Glacial overprint

During the Wisconsinan glaciation (peaking ~22,000 years ago), the Laurentide Ice Sheet advanced south across the plateau and stalled along a roughly diagonal line through Monroe and Pike counties. The plateau itself was overtopped by ice; the unglaciated escarpment falls away to the south.

The glacier’s retreat left:

• Till blankets — unsorted glacial debris covering the plateau’s surface, much of it acidic and poorly drained
• Kettle holes — depressions left by buried ice blocks that melted out, now occupied by bogs and small lakes
• Glacial lakes — [[lake-wallenpaupack|Lake Wallenpaupack]] basin (later dammed), [[lacawac-sanctuary|Lake Lacawac]] (untouched, now a research preserve), Promised Land Lake basin, Long Pond
• Disrupted drainage — the plateau’s surface streams meander unpredictably, creating wetlands wherever water can’t find a clear path off the tableland

The poorly drained surface and acid till together explain why peatlands — globally rare south of New England — persist on the plateau.

Climate consequences

The plateau is meaningfully colder than the surrounding lowlands. Temperatures average 5–10°F lower than nearby Stroudsburg or Wilkes-Barre at any given hour; growing seasons are 2–3 weeks shorter. Annual snowfall on the plateau routinely exceeds 60 inches, vs. 30–40 in the valleys.

This cold-pocket effect is the climatological reason the [[poconos|Poconos]] hold boreal-relict species ([[tamarack|tamarack]], Atlantic white cedar, snowshoe hare, blackpoll warbler in migration) at a latitude where they otherwise wouldn’t survive.

Ecological consequences

• Cold-water fisheries — headwater streams stay below 68°F through summer, supporting native [[brook-trout|brook trout]]
• Boreal-affinity peatlands — [[sphagnum-moss|sphagnum]] bogs with sundew, [[pitcher-plant|pitcher plant]], leatherleaf, bog laurel
• Hemlock-northern-hardwood forest — the dominant upland canopy
• High avian diversity in summer — boreal-breeding warblers (blackburnian, [[magnolia|magnolia]], Canada) reach their southern range edge here

Why this matters for the platform

The [[poconos|Poconos]]’ relict ecology is climate-dependent in the strict sense — the cold-air pocket that the plateau creates is what keeps it intact. Modest warming compresses the cold pocket from below; the boreal-affinity species lose their refuge. [[directory|The directory]]‘s substrate-builders on the plateau (TNC, the land trusts, the watershed associations) are working to keep the system viable as the climate envelope shifts.

See also

Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.

• Enables: [[glacial-kettle-bog]] · [[eastern-hemlock-forest]]
• Substrate of: [[poconos]]
• Contains: [[brook-trout]]
• Contains: [[glacial-kettle-bog]]

Sources

• USGS Geologic Map of [[poconos|Pennsylvania]] (Pocono Formation extent)
• PA DCNR Geology of the [[poconos|Pocono region]] (state geological survey)
• The Nature Conservancy, Pocono Plateau Conservation Plan (publicly summarized)