In reply to Sl@te Head:
We´ve been in loads of the quarries, slabs don´t really exist because of the way it is cut out. They are dead vertical walls and smooth as can be since they are diamond cut. The entertainment is trying to climb the internal corners using the remains of the vertical bore-hole and any inclusions and solution holes. Not so easy!
It is mostly marble but the guide is correct since this is only another form of limestone, loads of climbing areas are really on marble but it would only confuse climbers!