BEDDING, GRADED

The fact that graded bedding in clastics by virtue of the gravity stratification can be used if the rocks are intensely deformed but not metamorphosed can be used to determine the facing direction. But another mechanistically significant point is that the fabric developed in such rocks shows on account of the progressive change in competence refraction that is as well gradual as the competence variation and gives rise to a sigmoidal cleavage or concave upward. The photograph produced is from Ramsay from the Helvetic Alps.