Giant stair steps
The striations on the rock in the photo to the right are oriented from the upper left to the lower right corners of the photo. Because striations parallel the ice flow direction, they indicate the orientation of flow. Without knowing the larger setting in which the rock is located, however, we cannot tell from the photo alone whether ice flowed from upper left to lower right or from lower right to upper left.
|Photo: W.C. Alden. 1902. USGS Photographic Library, photo awc00869. <http://libraryphoto.cr.usgs.gov/> Accessed June 2010.