Sentence:  Wherever a geologist directs his attention in the midst of a scene of <WSD>mountains</WSD>, traces of ruin and decay always meet his eye; and the lofty prominences of our globe, supposed to be the most permanent of nature's works, every where display unequivocal marks of the lapse and effects of time. 
Meaning of the word marked with <WSD> tags:  An elevation of land of considerable dimensions rising more or less abruptly, forming a conspicuous figure in the landscape, usually having a small extent of surface at its summit.