17.

The Frochet waterfall has the characteristic of being a cascade of tuff, also called travertine. Here the environment is fresh and shaded, which is favorable to the development of mosses. Under the action of water, the mosses petrify, and this forms the tuff, which is a calcareous rock.

The Chartreux bridge is built of tufa stone, very present in the area. It allows to cross the Cholet, and has long facilitated exchanges between Saint-Laurent-en-Royans and Saint-Jean-en-Royans. It was also a place of passage for the transport of coal from the Col de la Machine.

This arboretum was created in 1986 in place of an old landfill. In 2010, a collective is founded to energize the place, and events are set up around the theme of nature. Today, it is an area of biodiversity, conviviality and discovery, especially for schools.

Located at the entrance of the cemetery of Saint-Laurent-en-Royans, this Gallo-Roman stone is a funerary cippus of the 2nd century.The upper part of the stone forms a hollow within which offerings could be deposited. Latin inscriptions appear on the stone:"To Titus Sammius Tertiolus, employed in the writings of the aerarium (public treasury), died at the age of twenty-six, Connia Conniola to her excellent husband and Sammius Connius to her father."

In the gorges of Petits Goulets the Cascade Blanche and its white veil is a place of freshness. The water of the Vernaison comes from Rousset en Vercors after having crossed the Grands and the Petits Goulets having incised the rock.