It happens that the rock surfaces will be somewhat polished and at least smoothed by the abrasive action of the ice and detritional rock fragments.
(It; happens; ) Context(It happens,List([0, 10))):(the rock surfaces; will be; somewhat polished and at least smoothed by the abrasive action of the ice and detritional rock fragments)
It happens,List([0, 10))
It the rock surfaces
happens will be
somewhat polished and at least smoothed by the abrasive action of the ice and detritional rock fragments