Many holes had been drilled in the face of the cliff of hard rock, and the charges stamped in.
黑体部分 the face 是中心词,而 of the cliff 是 face 的定语;the face of the cliff :峭壁的表面。of hard rock 是指 cliff 的构成成分,意思是说,“由岩石构成的这个峭壁”。of 的其中一个用法是表示“组成、构成关系”。 the cliff of hard rock = the cliff made of hard rock
又如:a team of five members = a team made up of five members 一个5人的团队;一个5人的小组