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they can be imbedded in marine strata, or before their casts can be taken there in stone.

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It is only natural that in strata formed in the sea, the fossils in general should be of fish or of sea animals and plants, and that fresh-water or land animals or plants should be a most rare exception. So in fresh-water strata amphibious animals and fresh-water productions prevail; and in beds of drift and alluvium, or sediment deposited on dry land,' land animals and plants. Where are the fossil remains of land quadrupeds found? In cavern deposits, in drift and alluviums deposited on dry land,' in filled-up lakes, in bogs, or frozen up in polar regions. Now all these land museums are not only modern, but they are superficial and temporary. They are liable to be washed into the sea; and their fossil contents must be destroyed before they can be redeposited in marine strata.

We have no museums for the collection of really ancient land existences. Marine strata are the museums for the collection of really ancient life; but their collections are very imperfect, except of those beings which wear their skeletons outside them. For it is not only that the external skeletons of shell-fish are infinitely more durable than internal skeletons, but the habits of the creatures make them, as they say, safe to be im

bedded. If land animals had only a millionth chance of permanent imbedding which shell-fish have, what Theria Cruickshanksiana and Sidebottomi we should behold!

'As weak as water' is the common saying; yet water, in the form of rain, destroys old continents, and in the form of mud water builds new continents.

That land should flow out to sea is as paradoxical, and appears as impossible, as that water should go up through the air. Yet both these impossibilities not only go on every day but all day long; and we see the water in the air as clouds, and the land in the water as muddy water. But it is only as muddy water that land goes out to sea, or as the finest sand. It is only as muddy water that the new emigrant continent takes passage to its destination. All the coarser material brought by floods to the shore remains there till the waves have ground it fine enough for carriage. And the waves they are never weary.' It is a large mill, and night or day never ceases to grind.

It is clear, however, that not a single bone of a land animal could be carried out to sea, except when a body, having sunk near the sea, rises again from putrescence and floats for a short time. But even in this case, except with an off-shore wind, the body would probably be cast ashore.

Or an animal may be floated out on a tree, or on an iceberg, and if not devoured may become fossil. I need not go farther to show the impossibility that nature should write us a perfect catalogue of foregone land animals, from such scanty materials, even if the archives which she has written were

accessible to us. With regard to land plants it is otherwise. They might all float out to sea for great distances; that is, till they are water-logged, till water has replaced the air which they contain.

To this provision we owe our coal-beds; and I think it somewhat puzzling that coal should be confined to the Paleozoic strata. On the west coast of Africa, immediately to the north of the equator, the Niger discharges from the mouths of its delta vast quantities of drift wood. Immediately to the south of the equator the Congou does the same. And I have been told by merchants, and by officers serving on that coast, that islands of wood with trees growing on them float out to sea from both these rivers. The admirable Rennel has chalked out for us the course of the current which must convey this drift vegetation across the Atlantic to the Gulf of Mexico. have all heard of the vast rafts formed in the Mississippi from the accumulation of drift timber. We have all heard of the enormous quantities of

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Drift and alluvium, or

drift wood discharged from the mouths of the Amazon, the Orinoco, and the tropical rivers of the north part of South America. What becomes of these vast magazines of carbon till they are so water-logged as to sink? Probably, as Lyell remarks, a large proportion takes passage by the Gulf Stream. And not improbably, vast beds of future coal may now be depositing in high northern latitudes, the greatest part of which may be composed of tropical plants. The tropics of the old world, as well as the new, are most probably at this moment storing their superabundant vegetation for the future warming of our northern descendants. If this is true, coal may be found in any stratum foregone or to come.

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deposit on dry dry land,' Principles,' chap. xiii.

land.'

Lyell heads a paragraph with No sediment on What, then, is the entire deposit of all alluvial plains? and of that part of all deltas which is above the level of the sea? Rivers may flow through alluvial plains for a continuous distance of hundreds, nay thousands, of miles from the sea, the whole of which alluvium has travelled there as muddy water. That is, every particle of the nearly flat surface has been held in suspension by the flooded rivers and deposited by them on dry land.'

I should also ask, what then is drift? Lyell would account for these beds as the remains of

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his favourite submarine denudation, previous to the elevation of the land. If so, why are they so full of the fossil remains of land animals? and how does the submarine theory apply to the drift bed near Behat, in India, mentioned in the ninth chapter, which, Captain Cautley tells us, was deposited within the memory of persons now living?' And how does it apply to the bed which covers the very ancient subterranean town' there? Was the present subterranean town formerly a submarine one? In sinking wells in the environs, masses of shingle and boulders have been reached resembling those now in the river channels of the same district (so we see how long the game which is now playing has been going on) under a deposit of thirty feet of reddish loam. Captain Cautley, therefore, who directed the excavations, supposes that the matter discharged by torrents has gradually raised the whole country skirting the base of the lower hills.'

As these are quotations from Lyell's own Principles,' may I not again ask, in his own words, if a false theory does not render him blind to facts which are opposed to his prepossessions, or conceal from him their true import when he beholds them ?'

I only mention these particular beds because the account of them may be easily referred to by

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