Forest physiography; physiography of the United States and principles of soils in relation to forestry . ormaissance Across the Cascade Range near the49th Parallel, Bull. U. S. Geol. Surv. No. 235, 1904, p. 35. 2 Smith and Willis, The Physiography of the Cascades in Central Washington, Prof. PaperU. S. Geol. Surv. No. 19, 1900, p. 58. CASCADE AND SIERRA NEVADA MOUNTAINS l6l The lake lies in the canyon of the Stehekin-Chelan River and 32 milesof its length lies within the Cascade Mountains. The depth of the lakevaries from 1000 to 1400 feet, and as the waters surface is but 1079 feetabove the s
Forest physiography; physiography of the United States and principles of soils in relation to forestry . ormaissance Across the Cascade Range near the49th Parallel, Bull. U. S. Geol. Surv. No. 235, 1904, p. 35. 2 Smith and Willis, The Physiography of the Cascades in Central Washington, Prof. PaperU. S. Geol. Surv. No. 19, 1900, p. 58. CASCADE AND SIERRA NEVADA MOUNTAINS l6l The lake lies in the canyon of the Stehekin-Chelan River and 32 milesof its length lies within the Cascade Mountains. The depth of the lakevaries from 1000 to 1400 feet, and as the waters surface is but 1079 feetabove the sea, the bottom of the lake is at one place 300 feet below sealevel. The water is partially retained at its present level by a dam ofsand and gravel. It appears that the valley now partly filled by LakeChelan was occupied by a great mountain glacier that deepened andwidened the preglacial valley and steepened the valley walls, givingthem their present precipitous character. The glacial features of the northern Cascades are markedly asym-metric. For example, the U-shaped canyons that drain eastward to. Fig- 37- — Relief map of Mount Hood, Oregon, showing the eroded condition of thevolcano and the extent of its glacier systems. (U. S. Geol. Surv.) the Pasayten have northern walls of great simplicity and southern orshady walls carved into niches or hanging cirques of glacial average or prevailing aspect of the glacial cirques of the entire regionis about due northeast, a feature probably due to the preglacial topog-raphy, lesser insolation on that aspect, and a certain excess of snowaccumulated by drifting across the divide. The more favorable easterlyaspect is well illustrated by the glacial erosion of the Hozomeen range,the glaciers flowing eastward having eaten back into the heart of therange much more than their rivals in the western valleys. So markedis this feature that many of the higher peaks have a degree of asymmetrysuggesting a breaking wave.^ 1 Smith and Ca
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