CHAPTER XIII.

Successors of the exterminated Tribes.--The Gap slowly filled.--Proof that the Vegetation of a Formation may long survive its Animal Tribes.--Probable Cause.--Immensely extended Period during which Fishes were the Master-existences of our Planet.--Extreme Folly of an Infidel Objection illustrated by the Fact.--Singular Analogy between the History of Fishes as Individuals and as a Class.--Chemistry of the Lower Formation.--Principles on which the Fish-enclosing Nodules were probably formed.--Chemical Effect of Animal Matter in discharging the Color from Red Sandstone.--Origin of the prevailing tint to which the System owes its Name.--Successive Modes in which a Metal may exist.--The Restorations of the Geologist void of Color.--Very different Appearance of the Ichthyolites of Cromarty and Moray, 226-242