The bridge is built on an outcrop of ophites, a very hard rock that is very common in the entire Gerri area.
Although the river has supplied a large part of the materials used for construction in Gerri, within the village some of the more common rocks used for construction abound and can be observed.
The bridge is built on an outcrop of ophites, a very hard rock that is very common in the entire Gerri area.
Detail of an ophite pebble. Ophites are a variety of basic igneous rock, in greenish to black colours, with fine to medium grain. The outcrops forms intrusive bodies, which were sited among the clays and gypsum of the Middle and Late Triassic.
A part of the bridge is built with nodular limestones from the Devonian.
Outcrop of Triassic limestones over the spring on the side of the road.
Detail of the limestone at the Font del Raval spring in Gerri. They are from the Late Triassic.