Construction
    
    Base material
      Cut an irregular piece of mounting board or thin plywood. A couple of 
      the rocks above were based on thin card, but this warped a bit when 
      the PVA was applied, so I wouldn't recommend it. 
    Gap filling
    The best way to stick
      the stones down is with a blob of tile adhesive
      which will also fill any gaps beneath the stones.
     Otherwise you will need to fill
      the gap with plaster or filler.
      This can also be used to make the rocks look semi-embedded in the ground.
    Small Rocks
      To help make the rock look more natural, put some big patches of 
      PVA around the base and sprinkle them
      with plenty of small stones. These can be painted in the same way as 
      the rest of the base.
 
 Painting
    
   The best thing to do is to paint them as little as possible in order
    to let their natural colours show through.
  Optional Wash
    If the rocks are very pale then they may benefit from a dark brown 
    wash, but with these I didn't bother.
  Drybrush
    The only painting that these needed was a quick drybrush with  cream coloured paint. This was done at the same time as step 4) of the 
    basing as described below.
    cream coloured paint. This was done at the same time as step 4) of the 
    basing as described below.