Possible Clues:

• Building part often laid with public ceremony
• Inscribed thing made from a basis-pebble?
• Aunt fed onions to gathering as basic necessity
• Discovered rock is not a sound component for base of building
• Discovered on site -- not a terribly good basis for building
• Beginning of a big build-up?
• Block in basic construction
• Donation ten of us made to lay it
• Basis for a build-up
• Block the start of construction