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Updated: May 24, 2025
The presence of phosphatic nodules and bituminous matter in some of the lowest azoic rocks, probably indicates the former existence of life at these periods. But the difficulty of understanding the absence of vast piles of fossiliferous strata, which on my theory no doubt were somewhere accumulated before the Silurian epoch, is very great.
The fishing-ground of the geologist in the Silurian and Devonian periods is even more circumscribed than his, and belongs, besides, not to a living, but to a dead world, far more difficult to decipher. But the sciences of Geology and Palaeontology are making such rapid progress, now that they go hand in hand, that our familiarity with past creations is daily increasing.
Lyell has made similar observations on some of the later tertiary formations. Barrande, also, shows that there is a striking general parallelism in the successive Silurian deposits of Bohemia and Scandinavia; nevertheless he finds a surprising amount of difference in the species.
To the question why we do not find records of these vast primordial periods, I can give no satisfactory answer. Several of the most eminent geologists, with Sir E. Murchison at their head, are convinced that we see in the organic remains of the lowest Silurian stratum the dawn of life on this planet. Other highly competent judges, as Lyell and the late E. Forbes, dispute this conclusion.
It is in the second great epoch, the Silurian, that the cuttle-fish tribe, still fairly represented by the nautilus, the argonaut, the squid, and the octopus, first began to make their appearance upon this or any other stage. With these natural advantages to back them up, it is not surprising that the cuttle family rapidly made their mark in the world.
When we consider that in the human world, from the battles and dances of savages to the intrigues and entertainments of modern Courts and palaces, the attraction of man and woman for each other has played an unending part; and, that the most fierce ascetic religious enthusiasm through the ages, the flagellations and starvations in endless nunneries and monasteries, have never been able to extirpate nor seriously to weaken for one moment the master dominance of this emotion; that the lowest and most brutal ignorance, and the highest intellectual culture leave mankind, equally, though in different forms, amenable to its mastery; that, whether in the brutal guffaw of sex laughter which rings across the drinking bars of our modern cities, and rises from the comfortable armchairs in fashionable clubs; or in the poet's dreams, and the noblest conjugal relations of men and women linked together for life, it plays still today on earth the vast part it played when hoary monsters ploughed after each other through Silurian slime, and that still it forms as ever the warp on which in the loom of human life the web is woven, and runs as a thread never absent through every design and pattern which constitutes the individual existence on earth, it appears not merely as ineradicable; but it is inconceivable to suppose that that attraction of sex towards sex, which, with hunger and thirst, lie, as the triune instincts, at the base of animal life on earth, should ever be exterminable by the comparatively superficial changes resulting from the performance of this or that form of labour, or the little more or less of knowledge in one direction or another.
They became extinct at the end of the Silurian. The corals of the SYRINGOPORA family are similar in structure to chain corals, but the tubular columns are connected only in places. The blastoid is stemmed and armless, and its globular "head" or "calyx," with its five petal-like divisions, resembles a flower bud.
We should not forget that only a small portion of the world is known with accuracy. M. Barrande has lately added another and lower stage to the Silurian system, abounding with new and peculiar species. Traces of life have been detected in the Longmynd beds beneath Barrande's so-called primordial zone.
Seeing, for instance, that the oldest known mammals, reptiles, and fish strictly belong to their own proper classes, though some of these old forms are in a slight degree less distinct from each other than are the typical members of the same groups at the present day, it would be vain to look for animals having the common embryological character of the Vertebrata, until beds far beneath the lowest Silurian strata are discovered a discovery of which the chance is very small.
Beneath the black slates above described of the Llandeilo formation, Graptolites are still found in great variety and abundance, and the characteristic genera of shells and trilobites of the Lower Silurian rocks are still traceable downward, in Shropshire, Cumberland, and North and South Wales, through a vast depth of shaly beds, in some districts interstratified with trappean formations of contemporaneous origin; these consist of tuffs and lavas, the tuffs being formed of such materials as are ejected from craters and deposited immediately on the bed of the ocean, or washed into it from the land.
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