By Barbara Mattoon Soos Creek Wetland  Photo courtesy of Scott Smithson A plateau rises between the valleys of the Green and Cedar Rivers stretching from the Springbrook area of Renton to an area near the salmon hatchery south of Auburn, an area of approximately 70 square miles.    The plateau is drained from Renton in a southeasterly direction toward where it empties into the Green River by Soos Creek and several smaller creeks. The first white settlers claimed land in the valleys because it was more suitable for farming than the land on the plateau.  Later arrivals had to content themselves with the rockier soil on the plateau which being less suitable for farming, was better suited for dairying, raising poultry and livestock. Early settlers on the plateau were primarily from Scandinavia.  They were driven to emigrate by severely depressed economic conditions in Europe in the latter half of the 19th century.  The Puget Sound area was attractive to them because of its s