Geology
Ten thousand years ago, the receding glacier left deep outwash consisting of sand and gravel deposits that form the banks of the Seekonk River and the bluffs above it. On eroded trails and banks the yellow sand and small stones that underlie the topsoil are visible. Over time, decaying plant material formed the layer of topsoil that sustains the woods and undergrowth of Blackstone Park.
A neat fact: Cumberlandite, a mineral unique to Cumberland, RI, was carried from Cumberland by the glacier and deposited in the park. A number of pieces of this heavy black rock flecked with light crystals have been found and continue to turn up. Cumberlandite may also be found along the riverbank in Swan Point Cemetery.
Plant Life
Trees that predominate are oaks, American beech, and black birch, with a few maples and birch. Beneath the trees are many native blueberry bushes, clethra (summer sweet), and mountain laurel.
Wild Flowers and Plants:
Throughout the woods are thinly scattered wild flowers. These include the pink lady’s slipper, May apple, Solomon’s seal, and Canada mayflower.
Plants found along edges of the woods, particularly near the river, are wood aster, bayberry, sassafras, rosa rugosa, sweet fern, and sumac.
Plants found on the banks of York Pond at the end of Irving Avenue are elderberry, Joe Pye weed, goldenrod, bur cucumber, white snakeroot, evening primrose, milkweed, and touch-me-not (jewelweed). curly dock, blue vervain, polygonum persicaria (lady’s thumb—pink thumblike flowers), and false nettle, chicory along the rail north of the entrance to York Pond meadow, and blue flowering pickerel weed in the pond.
Invasive Species:
Invasive species in the park are: Japanese bittersweet, green briar, Japanese knotweed, Ailanthus (Tree of Heaven), purple loosestrife, garlic mustard, and multiflora rose. Poison ivy, which exists throughout the park, is a native plant.