Sentence:  [stanza 22] [...] Whose savage trample thus could pad the dank / Soil to a plash? toads in a poisoned tank, / Or wild cats in a red-hot iron cage— / [stanza 23] The fight must so have seemed in that fell <WSD>cirque</WSD>. 
Meaning of the word marked with <WSD> tags:  A curved depression in a mountainside with steep walls, forming the end of a valley.