Original: Bays form where weak ( less resistant ) rocks ( such as sands and clays ) are eroded , leaving bands of stronger ( more resistant ) rocks ( such as chalk , limestone , granite ) forming a headland , or peninsula .
Simplified: Bays form where weak rocks , such as sands and clays , are eroded , leaving bands of stronger rocks , such as chalk , limestone , or granite , forming a headland , or peninsula .