CHAPTER V.

STRATIFIED ROCKS OF MECHANICAL ORIGIN--THEORY DEVELOPED AND ILLUSTRATED.

Formation of Stratified Rocks ascribed to the Agency of Natural Causes--This Theory supported by Facts--The Argument stated--Examples of Mechanical Rocks--Materials of which they are composed--Origin and History of these Materials traced out--Process of Deposition--Process of Consolidation --Instances of Consolidation by Pressure--Consolidation perfected by Natural Cements--Curious Illustrations--Consolidation of Sandstone in Cornwall--Arrangement of Strata explained by intermittent Action of the Agents of Denudation, 87