Sentence:  Imperfect examples of concave shells are to be seen in the salient of El Capitan, which is itself an imperfect dome, not wholly massive throughout, that has been vigorously <WSD>gouged</WSD> by the Yosemite Glacier. 
Meaning of the word marked with <WSD> tags:  To make a groove, hole, or mark in by scooping with or as if with a gouge.