"quite abruptly the ground had changed from the snow covered grassy undergrowth to a variety of water worn stones , only partially obscured by snow , which stretched all the way to the tower . varying in volume from fist sized cobbles to barrel sized boulders and larger ; the dark rocks were irregularly worn by the action of the waves . clearly exposed by low tide , the rocks covered the shore the entire distance to the _ ..." What is the word in the blank space (_)? The answer is
tower