Page "Facies" Paragraph 9

Walther's Law of Facies, or simply Walther's Law, named after the geologist Johannes Walther, states that the vertical succession of facies reflects lateral changes in environment.

Conversely, it states that when a depositional environment " migrates " laterally, sediments of one depositional environment come to lie on top of another.

A classic example of this law is the vertical stratigraphic succession that typifies marine trangressions and regressions.

However, the law is not applicable where the contact between different lithologies is non-conformable ( i. e. sedimentation was not continuous ), or in instances of rapid environmental change where non-adjacent environments may replace one another.