Oak Harbor i t S k a g Sauk Suiattle Suiattle River B a y During the advance and retreat of Indian Reservation Glacial Landforms of the the Puget lobe, drainages around the ice sheet were blocked, forming multiple proglacial Camano Island Stillaguamish lakes. The darker colors on this Indian map indicate lower elevations, Reservation Puget Lowland and show many of these t S Arlington Spi ss valleys. The Stillaguamish, e a en P g n o Snohomish, Snoqualmie, and Striped Peak u r D r Hook a Puyallup River valleys all once t z US Interstate 5 Edi Sauk River Lower Elwha t S contained proglacial lakes. Klallam o u s There are many remnants of Indian g Port a Reservation US Highway 101 Jamestown Townsend a n these lakes left today, such as S’Klallam A Quimper Peninsula Port Angeles Indian Lake Washington and Lake d Reservation Sequim P Sammamish, east of Seattle. o m H P Miller Peninsula r t o a S T l As the Puget lobe retreated, i m Tulalip e o s w McDonald Mountain q r e Indian lake outflows, glacial D n s u i s s s Reservation i c e a m o a H S. F. Stillaguamish River v n meltwater, and glacial outburst e d a g Marysville B r B l r e a y a b flooding all contributed to y o y t Elwha River B r dozens of channels that flowed y a y southwest to the Chehalis River Round Mountain Lookout Hill Lake Stevens I Whidbey Island at the southwest corner of this n d map. Remnants of these l n channels can be seen along the Ned Hill e u o Everett eastern and southern edge of the t S n o colored area in the map. i Sultan River s Present-day Lake Kapowsin and e Mount Zion s Ohop Lake both occupy one of these s o channels. Today, the Chehalis River P Mukilteo P Snohomish River Snohomish flows through a wide valley that During was largely sculpted by the last ice ice-age meltwater. Dungeness River Port Gamble - U advance and retreat (in S’Klallam Indian Mill Creek the latest Pleistocene), an Reservation US Highway 2 Devils Butte Monroe extension of the Cordilleran ice sheet, called the G Puget lobe, covered the Puget Sound region (see location Lynnwood map below). Haystack Mountain E Mount Walker Edmonds Skykomish River The colored area of the map (at right) represents the Mountlake Terrace approximate maximum extent of the Puget Lobe during this Kenmore time period. During glacial maximum, the location of y Port Madison - T Woodinville a Poulsbo Suquamish modern-day Seattle (near the center of this map) was beneath B Indian Shoreline Reservation Bothell 3,000 feet of ice. b Mount Turner Toandos Peninsula Port Lake Duvall N. F. Tolt River o Forest b Madison Park All of the land and waterways in this region were shaped, at a Dosewallips River least in part, by the glacial ice of the Puget lobe. Many D large-scale glacial landforms are preserved in the landscape Manette Peninsula P Kirkland S. F. Tolt River n Redmond o today. In this lidar*-derived map, landforms such as to r g n t i h drumlins, kettles, eskers, and glacial stream channels Duckabush River Bainbridge s O a Island S W r Sammamish can be seen. Examples of these and other D e c k y a e h N. F. Snoqualmie River L landscape features are enlarged at bottom s a I n h r US Interstate 405 s l i e right. L d E O Seattle t l m l Bellevue a B i o a t m A y m a Most of Washington’s population S e US Highway 101 k Fuller Mountain N D lives in this region—the glacial a Hamma Hamma River Green Mountain U u L 6 w geology influences many A Bremerton a Gold Mountain et m Inl r i lai s aspects of daily life, Sinc h Snoqualmie C Port Orchard W Cougar Mountain a Falls including transportation, N t er Issaquah w Mercer Island Newcastle a Snoqualmie water supply systems, Kitsap y Snoqualmie agriculture, and Indian US Interstate 90 Peninsula Reservation building D Renton M. F. Snoqualmie L a Tiger Mountain k e regulations. e (above glacial ice) D g C Burien River u Dow Mountain a s s N. F. Skokomish River h s m O Tukwila a a n P Vashon E O s a o Island Lake Youngs s Sea Tac v t S. F. Snoqualmie River l P H o Cedar River C a s s S. F. Skokomish River T h a Des Kent e g G r e Moines eat 1 Bend Maple Valley Maury Island Covington Mason Lake Vance Creek Sugarloaf Mountain Gig Harbor Skokomish 1 D e Federal Way t a l c o s a g Indian e P a s l C Reservation n o Auburn I m m e en s B c Green River a C a em y e C a nt r r US Interstate 5 Pacific I Harstene Island n Fox Island Tacoma Key Peninsula l Milton e t Muckleshoot Fife Indian Shelton Squaxin Tacoma Narrows N University Reservation Indian Edgewood 2 Reservation i Place s McNeil Puyallup Lake q Tapps Dayton Peak Island Indian u Sumner a Reservation Enumclaw l l y t Bonney Lake White Star l e R Anderson Lakewood Puyallup Pinnacle Peak In en e Island 1 Drumlins - tt a o c Drumlins (or fluted T t h e ridges) are geologic l Inlet White River features where n American Lake I Dupont movement of the ice d sheet smooths glacial d Eld u Orting South Prairie Creek sediment into elongated Skookum Creek B 3 teardrop shapes. Drumlins align in the direction of the ice Kennedy Creek Carbon River flow and are evident across US Highway 101 Olympia Lacey 5 most of the Puget Lowland. Nisqually Spar Pole Hill 2 Puget lo Indian Mima Mounds - Intriguing features be d Reservation rai called Mima Mounds are found on (ice-age na Tumwater Mima Prairie and in several outwash Che ge ha c channels in the southern part of this li ha McLane Creek 3 s R n Black Lake map. Composed of organic-rich, sandy iv n e e soil, Mima Mounds on this map are only r l Lake Kapowsin ) Puyallup River found on the most recent glacial outwash What is Lidar? deposits. The origin of the mounds has been * Yelm The fine detail depicted on this Tanwax Lake 4 debated for decades and a consensus on their map is the result of lidar. Lidar is formation has not yet been agreed upon. a remote-sensing technique that US Interstate 5 uses light pulses to rapidly collect 3 a very large quantity of elevation Kettles - Glacial kettles are depressions that form when points across large areas. a retreating glacier leaves a bit of ice behind which then Ohop Lake To learn more about lidar in 2 becomes buried by sediment shed from glacial streams. Washington visit: When the block of ice melts, the sediment collapses, forming www.dnr.wa.gov/lidar 4 a kettle. Kettles can be dry or filled with water, depending on Lemon Hill Tenino their depth and the level of groundwater in the area. Black River 4 Eskers - Eskers are snake-shaped landforms that are often found near the glacier’s terminus. Eskers are formed when rivers that are Jones Hill 5 Co rd i l l e ra n i c e s h e e t underneath, on top of, or within a glacier, transport pebble- to cobble-sized Nisqually River gravel that is exposed once the glacier retreats. The resulting landform is a Scatter Creek sinuous ridge of gravel that runs roughly parallel to the direction of ice flow. e b o l 5 t Outwash Channels - Dozens of stream channels were created by glacial lake e Deschutes River fault g u P outflows, glacial meltwater streams, and glacial outburst floods. Today, many of the channels no longer transport water or have smaller streams occupying them than the N streams that formed them. miles 6 Fault scarps - Sharp breaks in the fluted topography make it easy to identify geologically recent 0 10 20 faults, such as this one called the Toe Jam Hill fault on Bainbridge Island west of Seattle, which is 6 part of the Seattle fault zone. www.dnr.wa.gov/geology ©2017 Washington Geological Survey.