What is "quags"

Usage examples of "quags".

Just the deep silence that comes to the marshes when a blanket of snow covers the bogs and quags, silences their gurgles and gloops and sends all the slimy crea­tures back into the stillness of the mud.

Out over the marshes it traveled, covering the brackish marsh water with a thick white layer of ice, freezing the bogs and quags and sending the marsh creatures burrowing down into the depths of the mires where the frost could not reach.