The Classification of Cross‐stratified Units. With Notes on Their Origin

A descriptive classification of cross‐stratified units is proposed based on six objective criteria, and diagnoses are given for fifteen distinct kinds of cross‐stratified unit recognised with their aid. The origin of each kind is discussed in the light of existing observational, experimental, and theoretical studies. A three‐fold genetic classification of cross‐stratified units is tentatively outlined in which apparent origin and physical properties are closely correlated.