quaggy

In Scotland, they offered a way of avoiding a six-mile walk around a quaggy loch.

From The Guardian ● Dec. 24, 2016

There were stony tracts they painfully picked their way across, steep ridges to be clambered over, and belts of quaggy muskeg they must skirt, and the day's march grew rapidly shorter.

From Blake's Burden by Harold Bindloss

The long train had run out of the forest in the night, and was now speeding over a vast white level which lay soft and quaggy in the sunshine, for the snow had lately gone.

From A Prairie Courtship by Harold Bindloss

Weston, blinking about him, discovered in the quaggy mould two foot-prints half filled with water.

From The Gold Trail by Harold Bindloss

These reeds, again, grow in a peculiarly uncomfortable, quaggy bottom, which rises and falls, or rather which jumps and sinks when you step on it, like the seat of a very luxurious arm-chair. 

From Angling Sketches by Andrew Lang