Cretaceous sedimentary rocks, mostly marine (WAK;0)

State	Washington
Name	Cretaceous sedimentary rocks, mostly marine
Geologic age	Late Cretaceous; possibly Eocene
Original map label	K
Comments	Dragovich and others, 2002, maps the northernmost San Juan Islands (Patos, Sucia, and Matia Islands) in this unit as Eocene continental sedimentary rocks correlative with the Chuckanut Formation; Stuarts, Johns, Waldron, Flattop, Skipjack Islands, and the northern shore of Orcas Island consist of the Nanaimo Group of Cretaceous age. Both groups have similar lithology. Huntting and others, 1961, listed the Spieden group and Winthrop sandstone in this unit. The Spieden Formation mapped in the WAJK unit more recently (sole occurrance is on Spieden Island just north of San Juan Island) (Brandon, 1989). The Winthrop formation appears in northern Okanogan County (see unit WAKu), but not in this unit which is exclusive to the northern San Juan Islands.
Primary rock type	sandstone
Secondary rock type	conglomerate
Other rock types	shale; coal
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed) Sedimentary > Clastic > Conglomerate (Bed) Minor Sedimentary > Clastic > Mudstone > Shale (Bed) Incidental Sedimentary > Coal (Bed)
Map references	Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.
Unit references	Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000. Brandon, M. T., 1989, Geology of the San Juan-Cascade Nappes, northwestern Cascade Range and San Juan Islands, in Joseph, N. L. (Ed.), Geologic Guidebook for Washington and Adjacent Areas: prepared for the 85th Annual Meeting of the Cordilleran Section, Geological Society of America, May 8-11, 1989, Spokane, Washington: Washington Division of Geology and Earth Resource Infomation Circular 86, p. 137-162. Johnson, S. Y., 1981, Stratigraphy, Sedimentology, and Paleogeographic Significance of Spieden Group, San Juan Islands, Washington: American Association of Petroleum Geologists (AAPG) Bulletin, v. 65, no. 5, p. 942. Dragovich, J. D., Logan, R. L., Schasse, H. W., Walsh, T. J., Lingley, W. S., Jr., Norman, D. K., Gerstel, W. J., Lapen, T. J., Schuster, J. E., Meyers, K. D., 2002, Geologic Map of Washington-Northwest Quadrant: Washington Division of Geology and Earth Resources Geologic Map GM-50, scale 1:250,000.
Geographic coverage	San Juan