CHAPTER XIIL. 
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 Sys- 
tem owes its Name. — Successive Modes in which a Metal may ex- 
ist. — The Restorations of the Geologist void of Color. — Very dif- 
ferent Appearance of the Ichthyolites of Cromarty and Moray. 
Tue period of death passed, and over the innumerable 
dead there settled a soft, muddy sediment, that hid them from 
the light, bestowing upon them such burial as a November 
snow-storm bestows on the sere and blighted vegetation of 
the previous summer and autumn. For an unknown space 
of time, represented in the formation by a deposit about fifty 
feet in thickness, the waters of the depopulated area seem to 
have remained devoid of animal life. A few scales and 
plates then begin to appear. The fish that had existed out- 
side the chasm seem to have gradually gained upon it, as 
their numbers increased, just as the European settlers of 
America have been gaining on the backwoods, and making 
themselves homes amid the burial-mounds of a race extinct 
for centuries. For a lengthened period, however, these finny 
settlers must have been comparatively few — mere squatters 
in the waste. In the beds of stratified clay in which their 
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