Rock faces (6)
I believe the answer is:
cliffs
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rock faces</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for cliffs that I've seen before include "Sheer rock faces overlooking sea" , "Steep rock-faces as on coast" , "Crags, Precipies" , "High, steep rockfaces" , "Precipices" .)