Sentence:  ... at laſt I left them / I'th' filthy mantled <WSD>poole</WSD> beyond your Cell, / There dancing vp to th' chins, that the fowle Lake / Ore-ſtunck their feet. 
Meaning of the word marked with <WSD> tags:  A small and rather deep collection of (usually) fresh water, as one supplied by a spring, or occurring in the course of a stream; a reservoir for water.