All the gathered shells were crushed into grit by the old windmills.
The coarse grit was used in chicken feed, for better digestion and extra calcium for stronger eggshells.
Finely ground grit was mainly used in cement.
Did you know that the color of the shells differs per coastal town? Around Noordwijk blue tones are more common.
Return to the Schoolstraat and walk towards the watertower.