The river's course is through upper and middle Devonian rocks, predominantly the Upper Delabole Slates, Trevose Slates and Polzeath Slates that stretch to the coast, although Pentire Head is composed mainly of pillow lavas.
The river's course is through upper and middle Devonian rocks the Upper Delabole Slates. This is predominantly. The river's course is through upper and middle Devonian rocks Trevose Slates. This is predominantly. The river's course is through upper and middle Devonian rocks Polzeath Slates. This is predominantly. This Polzeath Slates stretch to the coast. Pentire Head is composed mainly of pillow lavas.