Figure 5b. Crag-and-tail feature in phyllitic bedrock at Brown Woods showing unique ice-flow direction (see Figure 4 for location). The crag is composed of hard quartz and is surrounded by softer phyllite. The glacier abraded the soft phyllite more easily than the quartz pod. The quartz pod protected phyllite on the lee side and produced a comet-like tail pointing in the direction of ice flow. For this reason, crag-and-tail features are valuable as unique ice-flow direction indicators.
Last updated on January 13, 2009