Striations and grooves attest to a methodical and relentless pressure which was exerted on the grounded materials by the imbedded materials in the moving ice. Often the grooved rock surface was planed smooth or faceted as well. When the ice body moved up and over raised areas of resistant rock, imbedded rocks impacted the leeward side of the resistant rock with a great downward force to form the circular and semicircular patterns known as chattermarks. Large boulders plucked from the bedrock could have been carried tens or hundreds of miles by the glacier. The large boulders left behind by the melted glacier are known as erratics .
Rock piles on farm landscapes attest to the variation of materials carried by glaciers.
Moving meltwater can sort the sediments into distinct sand or gravel lenses. When buried, these lenses formed shallow water aquifers. When glacial activity crushed carbonate rocks such as limestone or dolomite, the carbonates solubilized in the till during the post-glacial period and precipitated on the buried rock surfaces during wetting and drying cycles. Carbonate scale occurs on the underside of rock surfaces of all sizes. Gravel and sand from glacial outwash fill many stream channels in eastern South Dakota.