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| Northrup Canyon is a glaciated coulee east of Steamboat Rock along Highway 155. This image shows a grass filled valley that was likely once a glacial lake. The high cliffs in the distance are Columbia River Basalt. The conifer forest grows amongst outcrops of glacier carved granite. The glaciers carved roche moutonnees in the granite. A roche moutonnee is a small bedrock hill that typically is rounded by glacial erosion on the uphill side, but has steep cliffs on the downhill side caused by the moving ice sheet plucking away blocks of bedrock. The orientation of roche mountonnees can indicate the direction of ice movement. In many places, the surface of the granite still preserves striations (scrape marks left by rocks dragging along in the bottom of the ice sheet). |
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