Post a bug report on the raise land spell if it can create mountains (as it doesn't fit the description, nor is there any reason to have create mountain as a seperate spell). I'm not at home to test this, but I assume you have created maountains with raise land.
I wuold actually classify blocking paths, and creating paths as two very seperate beasts. IMO creating paths should be easy and cheap. Undoing paths and blocking off areas should be a large investment.
Therefore, assuming lower land and raise land can NOT create UNPASSABLE terrain, then they should be cheap. However, if the desciption is wrong, and the intended effect is that the spells CAN create UNPASSABLE terrain, then they are under priced and I wholly agree with peoples' sentiments on the issue.
If the description is right and the ability to create impassable terrain is a bug, then I still think this whol issue goes away.
basically the crux of my opinion lies in whether the spell can/should be able to create terrain which is impassable. If yes, cost increase +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
if no, then cost can be cheaper cheaper