The World Before the Deluge

by Louis Figuier

Shells have been found in the Upper Boulder Clay of Lancashire, at Hollingworth Reservoir, near Mottram, by Messrs. Binney, Bateman, and Prestwich, at an elevation of 568 feet above the sea, consisting of Fusus Bamffius, Purpura lapillus, Turritilla terebra, and Cardium edule. The clay is described by Mr. Binney as sandy, and brown-coloured, with pebbles of granite and greenstone, some rounded and some angular. All the above shells, as well as Tellina Balthica, have been found in the Upper Clay of Preston, Garstang, Blackpool, and Llandudno, by Mr. De Rance, who has also found all the above species (with the exception of Fusus), as well as Psammobia ferroensis, and the siliceous spiculæ of marine sponges, in the Lower Boulder Clay of West Lancashire. He has described the ordinary red Boulder Clay of Lancashire as extending continuously through Cheshire and Staffordshire into Warwickshire, gradually becoming less red and more chalky, everywhere overlying intermittent sheets of “sands and shingle-beds,” one of which is particularly well seen at Leamington and Warwick, where it contains Pectens from the Crag, Gryphæa from the Lias, and chalk fossils and flints. The latter have also been found by Mr. Lucy in the neighbourhood of Mount Sorrel, associated with bits of the Coral Rag of Yorkshire. The gravels of Leicester, Market Harborough, and Lutterworth were long ago described by the Rev. W. D. Conybeare as affording “specimens of the organic remains of most of the Secondary Strata in England.”

The Rev. O. Fisher, F.G.S., has paid much attention to the superficial covering usually described as “heading,” or “drift,” as well as to the contour of the surface, in districts composed of the softer strata, and has published his views in various papers in the Journal of the Geological Society and in the Geological Magazine. He thinks that the contour of the surface cannot be ascribed entirely to the action of rain and rivers, but that the changes in the ancient contour since produced by those changes can be easily distinguished. He finds the covering beds to consist of two members—a lower one, entirely destitute of organic remains, and generally unstratified, which has often been forcibly indented into the bed beneath it, sometimes exhibiting slickenside at the junction.

There is evidence of this lower member having been pushed or dragged over the surface, from higher to lower levels, in a plastic condition; on which account he has named it “The Trail.”

The upper member of the covering beds consists of soil derived from the lower one, by weathering. It contains, here and there, the remains of the land-shells which lived in the locality at a period antecedent to cultivation. It is “The Warp” of Mr. Trimmer.

Neither of these accumulations occur on low flats, where the surface has been modified since the recent period. They both alike pass below high-water mark, and have been noticed beneath estuarine deposits.

Mr. Fisher is of opinion that land-ice has been instrumental in forming the contour of the surface, and that the trail is the remnant of its moraine profonde. And he has given reasons[112] for believing that the climate of those latitudes may have been sufficiently rigorous for that result about 100,000 years ago. He attributes the formation of the superficial covering of Warp to a period of much rainfall and severe winter-frosts, after the ice-sheet had disappeared.

The phenomena which so powerfully affected our hemisphere present themselves, in a much grander manner, in the New World. The glacier-system appears to have taken in America the same gigantic proportions which other objects assume there. Nor is it necessary, in order to explain the permanent existence of this icy mantle in temperate climates, to infer the prevalence of any very extraordinary degree of cold. On this subject M. Ch. Martins thus expresses himself: “The mean temperature of Geneva is 9° 5 Cent. Upon the surrounding mountains the limit of perpetual snow is found at 8,800 feet above the level of the sea. The great glaciers of the valley of Chamounix descend 5,000 feet below this line. Thus situated, let us suppose that the mean temperature of Geneva was lowered only 4°, and the average became 5° 5; the decrease of temperature with the height being 1° c. for every 600 feet, the limit of perpetual snow would be lowered by 2,437 feet, and would be 6,363 feet above the level of the sea. We can readily admit that the glaciers of Chamounix would descend below this new limit, to an extent at least equal to that which exists between their present limit and their lower extremity. Now, in reality, the foot of these glaciers is 5,000 feet above the ocean; with a climate 4° colder, it would be 2,437 feet lower; that is to say, at the level of the Swiss plain. Thus, the lowering of the line of perpetual snow to this extent would suffice to bring the glacier of the Arve to the environs of Geneva.... Of the climate which has favoured the prodigious development of glaciers we have a pretty correct idea; it is that of Upsala, Stockholm, Christiana, and part of North America, in the State of New York.... To diminish by four degrees the mean temperature of a country in order to explain one of the grandest revolutions of the globe, is to venture on an hypothesis not bolder than geology has sometimes permitted to itself.”[113]

In proving that glaciers covered part of Europe during a certain period, that they extended from the North Pole to Northern Italy and the Danube, we have sufficiently established the reality of this glacial period, which we must consider as a curious episode, as well as certain, in the history of the earth. Such masses of ice could only have covered the earth when the temperature of the air was lowered at least some degrees below zero. But organic life is incompatible with such a temperature; and to this cause must we attribute the disappearance of certain species of animals and plants—in particular, the Rhinoceros and the Elephant—which, before this sudden and extraordinary cooling of the globe, appear to have limited themselves, in immense herds, to Northern Europe, and chiefly to Siberia, where their remains have been found in such prodigious quantities. Cuvier says, speaking of the bodies of the quadrupeds which the ice had seized, and in which they have been preserved, with their hair, flesh, and skin, up to our own times: “If they had not been frozen as soon as killed, putrefaction would have decomposed them; and, on the other hand, this eternal frost could not have previously prevailed in the place where they died; for they could not have lived in such a temperature. It was, therefore, at the same instant when these animals perished that the country they inhabited was rendered glacial. These events must have been sudden, instantaneous, and without any gradation.”[114]