NATIONAL NATURAL LANDMARKS PROGRAM
Columbia Cascades Cluster
Sims Corner Eskers and Kames (1)
Wallula Gap (3)
Boulder Park and McNeil Canyon Haystack Rocks (4)
Rose Creek Preserve (5)
Nisqually Delta (7)
Steptoe and Kamiak Buttes (8)
Davis Canyon (10)
Grande Ronde Feeder Dikes (11)
The Great Gravel Bar of Moses Coulee (12)
Withrow Moraine and Jameson Lake Drumlin Field (14)
Drumheller Channels (15)
Point of the Arches (16)
Landmark Descriptions
Sims Corner Eskers and Kames (1)
This site contains the best examples of Pleistocene ice stagnation landforms in the Columbia Plateau and western United States. Although the Great Lakes region and New England contain similar features, those at Sims Corner are well preserved thanks to the arid climate.
Water gaps have been cut through several anticlinal ridges between Ellensburg and Yakima by the antecedent Yakima River. State Route 821 passes through the gap, where folded rocks illustrate results of tectonic stress and stream cutting.
Umtanum Ridge Water Gap (2)
Glacial-outburst waters that crossed the Channeled Scablands during the Spokane floods were channeled through Wallula Gap. For several weeks, as much as 200 cubic miles of water per day were delivered to a gap that could discharge less than 40 cubic miles per day. Ponded water filled the Pasco Basin and the Yakima and Touchet valleys to form temporary Lake Lewis.
Boulder Park and McNeil Canyon Haystack Rocks (4)
These two adjacent sites contain the greatest concentration and best examples of glacial erratics on the Columbia Plateau, possibly in the entire United States. The boulders provide important evidence for glacial erosion and transport, as well as the direction of movement and distribution of glaciers on the Columbia Plateau during the last glaciation.
The preserve constitutes the best remaining example of the aspen (Populus tremuloides) phase of the hawthorn (Crataegus douglasii) / cow parsnip (Heracleum lanatum) habitat type.
Two features make this petrified forest distinctive: the large number of genera and species represented, and the unusual preservation of fossils in lava flows.
Ginkgo Petrified Forest (6)
The delta supports one of the five best known examples of the Washington-Oregon Salt Marsh Subtheme of the Temperate Coastal Salt Marsh Theme in the North Pacific Border Region. It is a major resting area for migratory waterfowl in the southern Puget Sound region.
Steptoe Butte is the type example of a steptoe, an isolated hill or mountain surrounded by lava flows. Kamiak Butte is an excellent place from which to view the Palouse country and loess substrate.
The lower course of the Grande Ronde River has many excellent examples of entrenched meanders or goosenecks. These features record regional uplift and forced entrenchment of a stream in its pre-uplift meandering pattern. Two localities along the Grande Ronde make up the landmark.
Grande Ronde Goosenecks (9)
The site is one of the least disturbed and most extensive examples of antelope bitterbrush (Purshia tridentata) / Idaho fescue (Festuca idahoensis) shrub steppe remaining on the Columbia Plateau.
Grande Ronde Feeder Dikes (11)
The feeder dikes are known at only a few places. The best exposures are in this area along the north side of the Grande Ronde River. The dikes fed the voluminous Miocene Lava flows of the Columbia Plateau of southeastern Washington and northeastern Oregon.
The Great Gravel Bar of Moses Coulee (12)
This is perhaps the largest example of bars created by outburst floods on the channeled scabland. The bars are well preserved and have only sparse vegetative cover.
This landmark contains superb examples of mound topography in the North Pacific Border natural region.
Mima Mounds (13)
Withrow Moraine and Jameson Lake Drumlin Field (14)
Withrow Moraine is the only Ice Age terminal moraine in the Columbia Plateau natural region. The drumlin field is the best example of this type of feature within the natural region. Together they provide dramatic evidence of depositional and erosional processes that accompany continental glaciation.
The site is a spectacular tract of butte-and basin scabland and provides excellent geomorphic evidence for late Pleistocene catastrophic floods on the Columbia Plateau.
The landmark contains spectacular examples of the results of shoreline erosion. It also has a nearly pristine environmental spectrum ranging from rocky tideland to climax upland vegetation.
Grand Coulee is the largest coulee in the Columbia Plateau and is probably the world's finest example of a recessional cataract gorge.
Grand Coulee (17)
