When ice flows over a jointed outcrop, it presses the joints shut on the upstream side and smooths the rock off, producing a streamlined shape.
(ice; flows; over a jointed outcrop) (it; presses; the joints shut on the upstream side; T:When ice flows over a jointed outcrop) (the joints; shut; L:on the upstream side) (it; smooths off; T:When ice flows over a jointed outcrop)
ice it the joints it
flows presses shut smooths off
over a jointed outcrop
the joints shut on the upstream side T:When ice flows over a jointed outcrop
L:on the upstream side
T:When ice flows over a jointed outcrop