Within the units of the George Washington Memorial Parkway are found the aquatic (streams, river banks, and vernal pools) and terrestial habitats needed by the 16 species of amphibians that have been identified here. These include seven species of frogs, Northern Cricket Frog (Acris crepitans), Spring Peeper (Pseudacris crucifer), Gray Tree Frog (Hyla versicolor/chrysoscelis), Bull Frog (Rana catesbeiana), Green Frog (Rana clamitans), Pickerel Frog (Rana palustris), and Wood Frog (Rana sylvatica), three species of toad, American Toad (Bufo americanus), Fowler's Toad (Bufo woodhousii fowleri), and Eastern Spadefoot Toad (Scaphiopus holbrookii), and six species of salamander, Spotted Salamander (Ambystoma maculatum), Marbled Salamander (Ambystoma opacum), Northern Dusky Salamander (Desmognathus fuscus), Two-lined Salamander (Eurycea bislineata), Longtail Salamander (Eurycea longicauda), and Red-backed Salamander (Plethodon cinereus). The Eastern Spadefoot Toad was discovered in Great Falls Park in 2003 and other species of amphibians are expected to be found as search efforts increase. Additionally, the White-spotted Slimy Salamander (Plethodon cylindraceus) is known from historical records near the mouth of Spout Run and Pimmit Run.