Geology of Skye with the development of an ice cap centred on the Cuillin and Red Hills. The main ice sheet that flowed westwards from the Scottish mainland was diverted around this upland area. The island is covered by large areas of glacial till, left behind when the ice melted. Geology of Skye The geology of Skye in Scotland is highly variable and the island's landscape reflects changes in the underlying nature of the rocks. A wide range of rock types are exposed on the island, sedimentary, metamorphic and igneous, ranging in age from the Archaean through to the Quaternary. The oldest rocks
Hills in the Puget Lowland as Lake Washington; and numerous kettle lakes, and Puget Sound itself. High points on the plateau remain, most of which are a drumlin (rocky glacial debris), or a bedrock intrusion that predated glaciation. Hills above 500 feet are considered exceptional. Hills are glacial deposits unless otherwise noted. King, Pierce and Snohomish Counties run up to the crest of the Cascades where their high points reside; therefore, the Cascades and attached foothills are excluded. Likewise for Thurston County in the Mount Rainier area, and Mason County's Olympic Mountains foothills. Landforms north of the Tacoma Narrows (Island, King, Kitsap, Pierce and Snohomish