Seattle city has over of parkland. Seattle is located between the saltwater Puget Sound (an arm of the Pacific Ocean) to the west and Lake Washington to the east. The city's chief harbor, Elliott Bay, is part of Puget Sound, which makes the city an oceanic port. To the west, beyond Puget Sound, are the Kitsap Peninsula and Olympic Mountains on the Olympic Peninsula; to the east, beyond Lake Washington and the Eastside suburbs, are Lake Sammamish and the Cascade Range. Lake Washington's waters flow to Puget Sound through the Lake Washington Ship Canal (consisting of two man-made canals, Lake Union,
Puget Sound faults geologic province is the approximately 50 million year (Ma) old marine basalts of the Crescent Formation, part of the Siletzia terrane that underlies western Washington and Oregon. East of Puget Sound the basement of the Cascades province is various pre-Tertiary (older than 65 Ma) metamorphic rock. Somewhere between Puget Sound and Cascades foothills these two geological provinces come into contact. As the juxtaposition of various disparate tectonic structures in northwest Washington requires significant strike-slip movement, it is further expected that this contact will be a major fault. The northern end of the Crescent Formation (aka Metchosin Formation) has been identified