Figure 2. Prior to glacial retreat, the bedrock surface was abraded by rock debris dragged along under great pressure at the base of the ice sheet. The photo shows parallel glacial grooves on a ledge surface immediately east of the Palmer Hill delta. Coupled with other evidence from nearby areas, the trend of the grooves indicates southeastward ice flow (150°), toward the upper left as seen in this view.
Last updated on January 5, 2011