types of liverock

[kuatto]

Most of the liverock i see looks the same except for the tonga rock.I'm looking for flat,plate-like pieces,to build caves and shelves.Is there a type of rock like this or is it just luck of the draw when it comes to finding pieces like that?I did manage to find a huge piece that was hollow with niece cave enterance(was like a suppries bag,full of all kinds of critters).

Jim