THE ANTIQUITY OF LIFE.

Globe, Volume IV, Issue 415, 11 October 1875, Page 4

THE ANTIQUITY OF LIFE.

[Scientific American.'] When Lyell and the rest of the uniformitarian school of geology began to attribute all geological changes to the protracted operation of the influences now remodelling the earth’s surface, sunshine and showers, rivers and seas, arctic frosts and tropic heats, slow risings and sinkings of the earth’s crust, with their attendant quakings and volcanic outbursts, the growth of vegetation, and the slowly accumulating deposits of coral polyps and other forms of animal life—it was objected that time was too short for such proceedings. Men had scarcely begun to question Usher’s six thousand years of Biblical chronology, and their imaginations were incapable of spanning monotonous milleniuras marked by no catastrophes. The Niagara could not have carved its six mile gorge at its present rate, for that would leave no time for antecedent operations. By Darwin’s day, such objections were worn out. Men had become accustomed to granting hundreds of millenniums for the periods of the geologist; yet they stood aghast at the’demand for more. Geology had been modest in its requirements compared with the rising science of biology. Allowance was asked not merely for the geologists rock-recorded ages, but for gaps in the record, for pages destroyed, and for measureless periods during which no records were kept in parts accessible to man, Darwin’s theory called for an extension of time compared with which that of the geological record was small, and his opponents refused. A theory, they said, which requires such boundless concessions of time cannot possibly be true. Now we learn that, whatever objections may be urged against the evolution theory, lack of time for the slow development of creation is not one of them. The soundings of the Challenger expedition give a clue to ages of life whose duration dwarfs to insignificance that of the periods between the Lower Silurian and the present, the limits formerly set for the duration of life upon the earth. The addition of the vast periods covered by the deposition of the many thousand feet of Cambrian and Laurentian rocks, with their shadowy traces of life, does not bring us [sensibly nearer the beginning; nor is the light they hint of any guide to a comprehension of the swarms of living things which sported in the waters of those primeval oceans, or inhabited their shores. We have given elsewhere a resume of the grounds on which Professor Wyville Thompson and his colleagues base their belief that the red clay, which covers such vast areas of the deeper ocean beds, is a residuum representing less tnan 2 per cent of the mineral matter of the microscopic animal and vegetable life which inhabits those waters ; and that it is identical with the basic clays of the extensive azoic formation known as slates, schists, and even gneiss and granite. If this position is sustained, as there is reason to expect it will be, by further observation, the antiquity of life surpasses the most ex travagant demands of biologists ; even the oldest known rocks, the fundamental granites as they have been considered, cannot be taken as sufficiently ancient to mark the time when life first made its appearance on earth. We must say of the organic as Hutton did of the inorganic world—“ We find no vestiges of a beginning,” for the farther back we go, the vaster are the measures of life’s duration, and their r > umber is countless.

The slow development of a thousand feet of coralline limestone covers a period not incompatible, however vast. Something like an approximate estimate can be made for the time required to deposit a thousand feet of sand in a lake bed or along a sea coast, But what arithmetic can number the ages required for the deposition of thousands of thousands of feet of the basic material of rock which at most can represent in its mass not much more than' the hundredth part of the mineral constituents of animal and vegetable life, so minute and so distributed that it barely tinges the deep sea water with a shade of green ? If the great deposit of red clay, now forming in the eastern valley of the Atlantic, were metamorphosed into slate and then upheaved, says Professor Huxley, it would constitute an azoic rock of enormous extent; and yet that rock is now forming in the midst of a sea which swarms with living beings, the great majority of which are provided with calcareous or siliceous shells and skeletons, and therefore are such as, up to this time, we should have termed eminently preservable. He might have added that the sea whose bed is so barren in organic remains lies between continents abounding with highly organised animal and vegetable life, with ancient cities, imperishable pyramids, and countless other traces of a higher than animal exists ence. Yet were the present continents submerged with the supposed elevation of the azoic sea bed the geologist of that period might say—as our geologists have been used to say, under similar circumstances—“ the earth was void of life when- these slates were jaid down I” Who shall say that higher forms of life could not have inhabited the shallow seas and the dry lands surrounding the deep seas wherein our “ primary” rocks were deposited? Who shall say that the vestiges of higher life discovered in the comparatively recent “ fossiliferous” strata afford anything like a complete history of life on earth, or deny to the student of biology unlimited time for bringing about the results he observes 1