ABSTRACT: Sedimentary cycles are repeated sequences in a stratigraphic section. This paper uses “stratigraphic cycles†to describe observed sequences of sediments in sections and “ process cycle†to describe processes that generated the cycles. Repetition of cycles is never completely identical and statistical methods of time series analysis are used to describe cyclicity. The study of process cycles requires the knowledge of a time scale and therefore relies heavily on the interpretation of the sedimentary record.