228 THE OLD RED SANDSTONE. 
those of the ichthyolite beds of Cromarty and Ross, nor these 
again from the impressions of the Arbroath pavement, or the 
Den of Balruddery. Nor is there much difficulty in con- 
ceiving how the vegetation of a formation should come to sur- 
vive its animals. What is fraught with health to the exist- 
ences of the vegetable kingdom, is in many instances a 
deadly poison to those of the animal. The grasses and water- 
lilies of the neighborhood of Naples flourish luxuriantly amid 
the carbonic acid gas which rests so densely over the pools 
and runnels out of which they spring, that the bird stoops to 
drink, and falls dead into the water. The lime that destroys 
the reptiles, fish, and insects of a thickly inhabited lake or 
stream, injures not a single flag or bulrush among the millions 
that line its edges. ‘The two kingdoms exist under laws 
of life and death so essentially dissimilar, that it has become 
one of the common-places of poetry to indicate the blight and 
decline of the tribes of the one by the unwonted luxuriancy 
of the productions of the other. Otway tells us, in describ- 
ing the horrors of the plague which almost depopulated 
London, that the ‘ destroying angel stretched his arm” over 
the city, 
«Till in th’ untrodden streets unwholesome grass 
Grew of great stalk, and color gross, 
es A melancholic poisonous green.” 
The work of deposition went on; a bed of pale yellow 
saliferous sandstone settled, tier over tier, on a bed of strati- 
fied clay, and was itself overlaid by another bed of stratified 
clay in turn. And this upper bed had also its organisms. 
The remains of its sea-weed still spread out thick and dark 
amid the foldings of the strata, and occasionally its clusters 
of detached scales. But the circumstances were less favora- 
