Geologic units in Kitsap county, Washington

Additional scientific data in this geographic area

Younger glacial drift (Pleistocene) at surface, covers 69 % of this area

Till. Hard, blue-gray to gray concrete-like mixture of clay, silt, sand, and gravel deposited as end or recessional moraine. Principally Wisconsin in age.

Younger glacial drift (Pleistocene) at surface, covers 13 % of this area

Advance and recessional outwash, stratified drift, and associated deposits. Primarily silt, sand, and gravel with some clay. Includes alluvium locally and scabland deposits of eastern Washington.

Older glacial drift (Pleistocene) at surface, covers 10 % of this area

Till, outwash, and associated interglacial deposits; sorted and unsorted gravel, sand, silt, and clay. Includes peat beds and non-glacial sediments locally. Mostly pre-Wisconsin in age.

Middle and lower Eocene volcanic rocks (Eocene) at surface, covers 4 % of this area

Dark-gray, course- to fine-grained, strongly chloritized basalt flows and breccia; includes pillow lava, deeply altered palagonite beds, amygdoidal and vesicular flows, and, locally, sedimentary rocks. Comprises outer volcanic belt in Olympic Peninsula, where manganese ore is associated with some submarine lavas.

Younger glacial drift (Pleistocene) at surface, covers 3 % of this area

Younger glacial drift, undivided. Till, outwash, and associated deposits; sorted and unsorted sand, gravel, silt, and clay. Includes some alluvium.

Oligocene-Miocene marine rocks (Oligocene) at surface, covers 0.6 % of this area

Massive to thin-bedded, coarse-grained sandstone, conglomerate, conglomeratic sandstone, shale, and sandy shale.

Tertiary dikes, sills, and small intrusive bodies (Middle to Late Tertiary) at surface, covers 0.3 % of this area

Dikes are commonly diabase; plugs and sills are generally andesite porphyry and dacite.