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Pleistocene
Pollen records for sites dating to the time of full North American glaciation during the last Ice Age (19,000-14,000 before present) are rare. Fortunately, one such site, studied by Maxwell and Davis (1972) is relatively nearby on the Allegheny Plateau. This is at The Glades, located in the Bittinger area of Garrett County, Maryland, approximately 33 miles to the south. Because Kimberly Run is also situated on the Plateau at a similar elevation, it may share some vegetation history.
Pollen from the Glades (which Maxwell and Davis call Buckel’s Bog) and elsewhere in the Northeast indicates tundra-like vegetation at the time of the last glacial maximum (during the Pleistocene), extending 300 kilometers or more south of the southern edge of the ice sheet in central Pennsylvania. The character of such habitats throughout the area south of the ice sheet in eastern North America is under some debate. Although there were areas of tundra-like vegetation between the ice sheet and evergreen forest to the south, in places it appears that there was little gap, so the pattern may have been a mosaic of tundra and forest.
The mid-Pleistocene pollen series from The Glades is dominated by sedges (Cyperaceae), and spruce and pine pollen is also present, which may support the concept of a tundra-forest mosaic. Maxwell and Davis (1972) suppose the conifer pollen was blown in from pockets of forest at lower elevations in the region.
Vegetation of these tundra areas was probably unlike that of today’s Arctic. For one thing, because of the lower latitude, summers were warmer. Vegetation of the open habitats may have been more similar to that of a grassy steppe.
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