Sentence:  They climbed over fallen and moss-grown logs; they <WSD>slushed</WSD> through shallow water; they crawled on their hands and knees under embankments and rocks, and at last, at Handsome's order, they stepped into a boat of some kind which the latter pushed away from the bank with a pole. 
Meaning of the word marked with <WSD> tags:  To slosh or splash; to move as, or through, a slushy or liquid substance.