Famous geologist Johannes Walther in 1894 developed the hypothesis that states when depositional environments shift, freshly deposited sediment will overlay previous depositional environments, and that vertical succession of facies reflect lateral changes in the environment of deposition. Simplified, the law states that if two facies are found to be adjacent within the rock record, with no unconformities, then they must have been deposited laterally in formation. The most common example of Walther’s law is shown in transgressive and regressive cycles seen in marine and coastal deposits