Wiktionary
n. The appearance of rock, after having been worn smooth by a passing glacier.
Wikipedia
Glacial polish is a characteristic of rock surfaces where glaciers have passed over bedrock, typically granite or other hard igneous or metamorphic rock. Moving ice will carry pebbles and sand grains removed from upper levels which in turn grind a smooth or grooved surface upon the underlying rock. The presence of such polish indicates that the glaciation was relatively recent (in geologic time scale) or was subsequently protected by deposition, as such polish will be subsequently lost due to weathering processes (such as exfoliation).
Usage examples of "glacial polish".
That much time would take care of any of the superficial signs, I should think, glacial polish or moraines or nanatuks.
The air is cold but still, and he can hear Hans and Frances inside their tent, arguing about glacial polish.