Yes, it's there. You're either not seeing it, or you're not in the right place. Unit palette. Then choose "neutral passive" from the drop-down menu wiht all the players. Then look in the buildings section. It's there.
As for your ramps question from your other thread, you use the ramp tool on cliffs to make them into ramps. Only 1-level cliffs can be made into ramps, and there needs to be some space below and above the cliff for the ramp to actually go through.