Though the chalk of the Champagne plateau is not far away, towards Reims, the immediate surroundings are of middle Eocene but the river has cut down into lower Eocene clay deposits like those at Chichester.
Meskipun batu kapur plateau Champagne tidak terlalu jauh, mengarah ke Reims, lingkungan sekitarnya adalah Eosin pertengahan tapi sungai ini telah membelah deposit tanah Eosin hilir seperti di Chichester.