Original sentence: Shelf Ice is a floating mat of ice, but unlike a pond or a small lake that freezes over, the shelf is not a uniform sheet of ice.The individual pieces, ice, in the case of shelf ice, are not connected, they only rest upon each other and many become jammed together
Edited sentence: Shelf ice is a floating mat of ice, but unlike a pond or a small lake that freezes over, the shelf is not a uniform sheet of ice.The individual pieces (ice in the case of shelf ice) are not connected; they only rest upon each other and many become jammed together