248 THE OLD RED SANDSTONE. 
ancient forest, seeing there is not a circumstance of difference 
between them ? 
We descend to the river side. The incessant action of the 
current has worn a deep channel through the leaden-colored 
silt; the banks stand up perpendicularly over the water, and 
downwards, for twenty feet together, — for such is the depth 
of the deposit, — we may trace layer after layer of reeds, 
and flags, and fragments of driftwood, and find here and 
there a few fresh-water shells of the existing species. In 
this locality, six thousand years are represented by twenty 
feet. The depth of the various fossiliferous formations united 
is at least fifteen hundred times as great. | 
We pursue our walk, and pass through a morass. Three 
tiers of forest trees appear in the section laid open by the 
stream, the one above the other. Overlying these there is a 
congeries of the remains of aquatic plants, which must have 
grown and decayed on the spot for many ages after the soil 
had so changed that trees could be produced by it no longer; 
and over the whole there occur layers of mosses, that must 
have found root on the surface after the waters had been 
drained away by the deepening channel of the river. The 
six thousand years are here represented by that morass, its 
three succeeding forests, its beds of aquatic vegetation, its 
bands of moss, and the thin stratum of soil which overlies 
the whole. Well, but it forms, notwithstanding, only the 
mere beginning of a formation. Pile up twenty such mo- 
rasses, the one over the other; separate them by a hundred 
such bands of alluvial silt as we have just examined a little 
higher up the stream; throw in some forty or fifty thick beds 
of sand to swell the amount; and the whole together will but 
barely equal the Coal Measures, one of many formations. 
But the marine deposits of the present creation have been, 
