Sparus cinctus, Carcharhinus sp. and fish coprolite

Falun is a detrital sedimentary rock, coming from a shallow sea, composed of numerous fragments of shells with bryozoans, fish teeth... and a sandy or clayey-sandy matrix. It reflects a shallow, warm-temperate marine paleoenvironment. Typical outcrops in France correspond to areas of marine transgression that geologists call the Falun Sea, and which cover the western and southern part of the country's current territory.

This sedimentary deposit marine usually dates back to the Cenozoic era and is dispersed over vast areas. The Faluns were formed from sediments deposited in a gulf during the Tertiary period, more precisely during the Miocene, that is, approximately 15 million years ago.