Geological facts; or, the crust of the earth, what it is, and what are its uses

by W. G. Barrett

FOSSIL FISH (ICHTHYOLITE) FROM LEWES.

Here let us again advert to the Deluge theory, not because our own minds are not satisfied on the point, but because theology and science alike demand a true statement of the facts of the case. We believe, as we said in a previous chapter, in the plenary inspiration of nature, just as we believe that the Scriptures were given by inspiration of God; and we are quite sure that both books, if they are not misinterpreted, will declare the glory of God in one common speech, and elevate the mind of man, to whom they speak, up to a more adoring trust and a profounder reverence. With Dr. Hitchcock we say, “It seems to me that the child can easily understand the geological interpretation of the Bible and its reasons. Why, then, should it not be taught to children, that they may not be liable to distrust the whole Bible, when they come to the study of geology? I rejoice, however, that the fears and prejudices of the pious and the learned are so fast yielding to evidence; and I anticipate the period, when on this subject the child will learn the same thing in the Sabbath school and in the literary institution. Nay, I anticipate the time as not distant when the high antiquity of the globe will be regarded as no more opposed to the Bible, than the earth’s revolution round the sun, and on its axis. Soon shall the horizon, where geology and revelation meet, be cleared of every cloud, and present only an unbroken and magnificent circle of truth.”[^[107]] But to return; this Deluge theory refers all existing fossils to “Noah’s flood,”—to that violent diluvial action, the graphic account of which is in the book of Genesis. Now, it is impossible to believe this if we look at a fossil: look, for instance, at this terebratula, and observe how perfectly uninjured it is, frail as is its shelly covering; or at this plagiostoma spinosa, and mark how susceptible it is of injury, and yet that its brittle spines are all unbroken; or at this inoceramus or catillus, and observe its delicate flutings, still in exquisite preservation, without fracture or distortion; or these specimens of echinites, the ananchytes ovata, or the spatanguscor-anguinum, and see the markings on the shell, the apertures of the mouth and stomach still perfect; who can see all this and not come to the conclusion, that these creatures, and thousands such as these, endured not only no violence in death, such as a deluge would suppose, but that at death they subsided quietly to the bottom of the sea, there to find a fitting sepulchre of soft cretaceous matter prepared for them, which in process of time was lifted up, to exhibit in a hard chalky bed their forms of pristine beauty?

In the upper chalk every one has seen the layers of flint, and marked their singular distribution, in layers; and here we would add, that the existence of flint in chalk is one of those hard nuts which geology has not yet cracked. The geologist, the chemist, and the zoologist have all puzzled themselves in vain to find a truly satisfactory origin for these nodules of siliceous matter. We have heard it suggested that they may be coprolites; but no one who examines the texture of a flint, can hold that theory, to say nothing of the idea that the coprolites have been preserved, while the animal remains have perished. We may sum up all we have to say about flints in the following words, from that useful little book, Chambers’s “Rudiments of Geology:”

“The formation of flint, within a mass so different in composition as chalk, is still in some respects an unsolved problem in geology. It occurs in nodular masses of very irregular forms and variable magnitude; some of these not exceeding an inch, others more than a yard in circumference. Although thickly distributed in horizontal layers, they are never in contact with each other, each nodule being completely enveloped by the chalk. Externally, they are composed of a white cherty crust; internally, they are of a grey or black silex, and often contain cavities lined with chalcedony and crystallized quartz. When taken from the quarry they are brittle and full of moisture, but soon dry, and assume their well-known hard and refractory qualities. Flints, almost without exception, enclose remains of sponges, alcyonia, echinida, and other marine organisms, the structures of which are often preserved in the most delicate and beautiful manner. In some specimens the organism has undergone decomposition, and the space it occupied either left hollow, or partially filled with some sparry incrustation. From these facts, it would seem that flints are as much an aggregation of silex around some organized nucleus, as septaria are aggregations of clay and carbonate of iron. This is now the generally received opinion; and when it is remembered that the organisms must have been deposited when the chalk was in a pulpy state, there can be little difficulty in conceiving how the silex dissolved through the mass would, by chemical affinity, attach itself to the decaying organism. Chalk is composed of carbonate of lime, with traces of clay, silex, and oxide of iron; flint, on the other hand, consists of 98 per cent. of pure silex, with a trace of alumine, oxide of iron, and lime. Silex is quite capable of solution: it occurs in the hot-springs of Iceland and most thermal waters; has been found in a pulpy state within basalt; forms the tabasheer found in the cavities of the bamboo, and the thin pellicle or outer covering of canes, reeds, grasses, &c.; and siliceous concretions are common in the fruits and trees of the tropics. All these facts point to a very general diffusion of silex in a state of solution; and whatever may have caused its abundance in the waters during the deposition of the upper chalk, there can be little doubt respecting the mode in which it has been collected around the organic remains of these early seas.”

At Scratchell’s Bay in the Isle of Wight, it will be seen that the flints are in a vertical position; and to the most casual observer the perpendicular arrangement of these flints will supply the strongest evidence of disturbance by upheaval from below. The bay in front, called Scratchell’s Bay, is a small but romantic indentation in the coast of the south side of the island, in which are the famous Needles. In the face of the cliff is a noble archway between 200 and 300 feet high, which has been created by the constant action of water eating and wearing away the lower beds; while the Needles themselves are only isolated masses of chalk, separated or eroded from the main land by the same erosive action. “To the late Sir Henry Inglefield belongs the merit of having first observed and directed attention to the highly interesting phenomena of vertical chalk strata, occasioned by the disruption and elevation of the eocene and cretaceous formations, which are so remarkably displayed in the Isle of Wight, where the vertical position of the strata, and the shattered condition of the flint nodules, thought still embedded in the solid chalk, may be conveniently studied in the cliffs in the neighbourhood of Scratchell’s Bay.”[^[108]]

With the study of the Chalk formation, we close what has been appropriately termed the “secondary period, or middle epoch of the ancient world;” of which it has been well said, “In reviewing the characters of the Cretaceous group, we have evidence that these varied strata are the mineralized bed of an extensive ocean, which abounded in the usual forms of marine organic life, as algæ, sponges, corals, shells, crustacea, fishes, and reptiles. These forms are specifically distinct from those which are discovered in the tertiary strata; in many instances, the genus, in all the species, became extinct with the close of the Cretaceous period. It affords a striking illustration of creative power, that of the hundreds of species which composed the Fauna and the Flora of the Cretaceous group, not one species passed into the succeeding epoch.”[^[109]]

Of that old ocean with its countless tenants we have already spoken, and conclude by applying to it the well-known lines of Montgomery, in his celebration of the coral insect in his “Pelican Island:”—

Millions of millions here, from age to age,

With simplest skill, and toil unweariable,

No moment and no movement unimproved,