As I just learned in the thread below, this would be a great opportunity to declare your ball unplayable under rule 28, as long as the rocks you speak of aren't out of bounds. You take a one stroke penalty and have to either drop within two club lengths but no closer to the hole, drop the ball as far back as you want as long as the unplayable lie position is directly between you and the hole, or hit from the spot of your previous stroke. Sounds bad, but its better than hacking away in the rocks and taking two or three strokes to get it out.

Unplayable Lie?

Did I get that right?

Now if the area is out of bounds different rules apply. You really should read the rules, it really helped me understand the game and clear up some misconceptions. The USGA has an interactive rule book online at:

http://www.usga.org/playing/rules/rules_of_golf.html