Southeastern Massachusetts, Cape Cod, and the islands of Nantucket and Martha's Vineyard consist of outwash from the last glacial maximum, which left thick glacial deposits of sand and gravel, providing the geologic foundation for a rare pine barren ecosystem.
Interspersed among the over 500,000 acres (80 km2) of fragmented pine barrens are dozens of coastal plain ponds, frost pockets, a wide variety of shapes and sizes of its signature tree, the fire-dependent pitch pine, the endangered Plymouth red-bellied turtles and other globally rare plant communities on top of deep deposits of glacially-deposited sands which filter and protect several sole-source aquifers including the Plymouth/Carver Sole Source Aquifer, the largest drinking water aquifer in Massachusetts.
Damaging recreation, such as off-road vehicle use on pond shores and in fragile pine barrens, was also on the rise but in recent years the area has also seen an increase in awareness of the importance and fragility of the ecosystem and a corresponding increase in the number of groups working to protect and preserve the natural bounty.
Sabatia kennedyana, New England boneset, golden hedge hyssops, pitch pine, and scrub oak, among other plant species, are found in this region.
The federally endangered Plymouth red-bellied turtle is a star attraction in the Massachusetts Coastal Pine Barrens.