Pre-Cambrian

“ THE LIFE OF THE CAMBRIAN PERIOD It is now for the first time that we find preserved in the offshore deposits of the Cambrian seas enough remains of animal life to be properly called a fauna. Doubtless these remains are only the most fragmentary representation of the life of the time, for the Cambrian rocks are very old and have been widely metamorphosed. Yet the five hundred and more species already discovered embrace all the leading types of invertebrate life, and are so varied that we must believe that their lines of descent stretch far back into the pre-Cambrian past. ”

“ Strips of Cambrian formations occupy troughs in the pre-Cambrian rocks of New England and the maritime provinces of Canada; a long belt borders on the west the crystalline rocks of the Blue Ridge; and on the opposite side of the continent the Cambrian reappears in the mountains of the Great Basin and the Canadian Rockies. In the Mississippi valley it is exposed in small districts where uplift has permitted the stripping off of younger rocks. Although the areas of outcrop are small, we may infer that Cambrian rocks were widely deposited over the continent of North America. ”

“ The fact that no Cambrian strata have been established by palaeontological evidence in the west of Ireland has made it equally difficult to establish any pre-Cambrian system. The great difference in character, however, between the Silurian strata at Pomeroy in county Tyrone and the adjacent metamorphic series makes it highly probable that the latter masses are truly Archean. ”

“ Life has been traced much below the Cambrian, but its record is very imperfect. The recent discoveries of more ample and varied life in the lower Palæozoic, particularly the Cambrian, implies, under current evolutional philosophy, a very great downward extension of life. In the judgment of some biologists and geologists, this extension probably reaches below all the pre-Cambrian terranes as yet recognized, though this pre-Cambrian extension is great. ”

“ The history of the Cambrian race is interesting not only to the antiquarian, but also to all real lovers of traditional and legendary lore. It is a race which had its origin in the mythical age, in the far back and remote past, in that period of the world’s history when intellectual and moral darkness covered the earth, and when gross darkness, like a black pall, enveloped the minds of the people. The country which this race originally occupied is simply a matter of conjecture—an unascertained fact ”

“ Yet we may at least, with all humility and self-abasement, ask our critics how they know that this great blank really exists, and whether it may not be possible that the swarming life of the early Cambrian may, after all, have appeared suddenly on the stage in some way as yet unknown to us and to them. ”

“ The few traces known of it prove little of its character, but they prove that life existed in a period far preceding Lower Cambrian time, and they foster the hope that it is only a question of search and favorable conditions to discover it. ”

“ Considered from the point of view of development, this fauna stands at least half-way, and some students of the ancient history of the earth place it as far as nine-tenths of the way, up the life column—that is, the time from the first appearance of life on the earth to the beginning of the Cambrian was at least as long and possibly nine times as long as the time that has since elapsed. ”

“ Nevertheless, we are beginning, as I believe, to feel firm ground after long walking through a region of quicksands; we are laying hold of principles of interpretation, the relative value of which we can not in all cases as yet fully apprehend—principles which sometimes even appear to be in conflict, but which will some day lead us to the truth. The name Cambrian has been given to the oldest rocks in which fossils have been found. This group forms the first chapter in the first volume, called Palæozoic, of the history of living creatures. Any older rocks are provisionally termed Archæan. ”

“ Crale estimates that about 60 million years have elapsed since the Cambrian period, but this, judging from the small amount of organic change since the commencement of the glacial epoch, appears a very short time for the many and great mutations of life, which have certainly occurred since the Cambrian formation; and the previous 140 millions of years can hardly be considered as sufficient for the development of the varied forms of life which already existed during the Cambrian period. ”

“ Having thus hastily glanced at the slender fauna of the rocks immediately below the Cambrian, we may now proceed to inquire a little more in detail into its true value and import as leading toward the beginning of life. I have already referred to the apparently sudden drop in the number of groups and of species below the base of the Cambrian, and have hinted that this may be an effect of temporary local conditions of deposit or of defective information. Another fact that strikes us is the diverse and miscellaneous character of the fossils that remain to us ”

“ On the other hand, those who hold the modern theories of gradual evolution repudiate the idea that the Lower Cambrian fauna can be primitive, and demand a vast series of changes in previous time to prepare the way for it. ”

“ The change in the species from the Lower to the Middle Cambrian fauna is very great.” He then goes on to show that in the Appalachian geosyncline there was another movement that shut out the Middle Cambrian Paradoxides fauna of the Atlantic realm from this trough, and all deposition as well.
Conclusions.—Accordingly it appears that everywhere in America the Lower Cambrian formations are separated by a land interval of long duration from those of Middle Cambrian time. These formations therefore unite into a natural system of rocks or a period of time. ”

“ Among the illustrious men and women of Cambria it would be difficult to select one to whom this book could be so appropriately inscribed as your ladyship. You are, and ever have been, the warm and sincere friend of my country; you are profoundly versed in her historic, poetic, literary, and legendary annals; you are a liberal and munificent contributor to almost every great movement designed to promote the social and intellectual, the moral and religious, welfare of the people of our ancient Principality; and you have attained a high and imperishable fame as a graceful and eloquent writer. ”

“ Carpenter have shown so much reason for believing, the remains of a living being, the discovery of its true nature carried life back to a period which, as Sir William Logan has observed, is as remote from that during which the Cambrian rocks were deposited, as the Cambrian epoch itself is from the tertiaries. In other words, the ascertained duration of life upon the globe was nearly doubled at a stroke. ”

“ The second argument of the paleontological opponents of the theory Darwin regarded as still more deserving of serious consideration.
The sudden manner in which several groups of species first appear in our European formations, the almost entire absence, as at present known, of formations rich in fossils beneath the Cambrian strata, are all undoubtedly of the most serious nature. The difficulty of assigning any good reason for the absence of vast piles of strata rich in fossils beneath the Cambrian system is very great. ”

“ Between Middle and Upper Cambrian time, however, there appears to be a complete transition in the Cordilleran trough, binding these two series of deposits into one natural or diastrophic system. Hence the writer proposes that the Lower Cambrian of America be known as the Taconic system. The Middle and Upper Cambrian series can be continued for the present under the term Cambrian system, a term, however, that is by no means in good standing for these formations, as will be demonstrated under the discussion of the Silurian controversy. ”

“ In Scandinavia occurs a well-developed series of Cambrian deposits, representing both the lower and upper parts of the Page 79 formation. In Bohemia, the Upper Cambrian, in particular, is largely developed, and constitutes the so-called "Primordial zone" of Barrande. Lastly, in North America, whilst the Lower Cambrian is only imperfectly developed, or is represented by the Huronian, the Upper Cambrian formation has a wide extension, containing fossils similar in character to the analogous strata in Europe, and known as the "Potsdam Sandstone." ”

“ Just as men, when their culture and their warfare advanced, clothed themselves with armour, and the most completely mailed survived the battle, so, generation after generation, the thicker and harder-skinned animals survived in the Archaean battlefield, and the Cambrian age opened upon the various fashions of armour that we there described. But, although half the story of life is over, organisation is still imperfect and sluggish. ”

“ His materials, he tells us, were collected from foreign rather than native sources, the latter of which had been put beyond his reach by circumstances. The Cambrian Annals give 570 as the year of his death. ”

“ Yet more remote, in the Cambrian, in an age of early life forms, an age recognized by the older geology as having almost ubiquitous warmth, the evidences of extensive glaciation have been brought to light. ”

“ But then it is urged that, though the Devonian rocks in one part of the world exhibit no fossils, in another they do, while the lower Cambrian rocks nowhere exhibit fossils, and hence no living being could have existed in their epoch. ”

“ In the bays and hollows of the distant shores the animal survivors of the great upheaval adapt themselves to their fresh homes and continue the struggle. But the rivers and the waves are at work once more upon the land, and, as the Cambrian age proceeds, the fringes of the continents are sheared, and the shore-life steadily advances upon the low-lying land. By the end of the Cambrian age a very large proportion of the land is covered with a shallow sea, in which the debris of its surface is deposited. ”

“ The periods we have already covered—the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian—form the Primary or Palaeozoic Era, to which the earlier Archaean rocks were prefixed as a barren and less interesting introduction. The stretch of time on which we now enter, at the close of the Permian, is the Secondary or Mesozoic Era. It will be closed by a fresh upheaval of the earth and disturbance of life-conditions in the Chalk period, and followed by a Tertiary Era, in which the earth will approach its modern aspect. ”

“ Turning now again to our table, we find that these creatures extend in unbroken lines back to the Lower Cambrian, the oldest beds in which we find any considerable number of organic remains, and leave all the other members of the Animal Kingdom far behind. ”

“ Lingula is found fossilized in the intermediate geologic eras. We have no proof that intelligent beings in ships from unknown lands did not dredge him up in Cambrian time. Five hundred million years is so absurdly long that there may have been at least twenty different flowerings of intelligence on the earth, having no relation to us. ”

“ In the Cambrian or oldest fossiliferous formations there is already a large and varied fauna, in which the leading groups of invertebrate life are represented. On no tenable hypothesis can these be regarded as the first organisms that came into being on our planet. They must have had a long ancestry, and as Darwin first maintained, the time required for their evolution may have been “as long as, or probably far longer than, the whole interval from the Silurian [Cambrian] age to the present day.” ”

“ All the important types of animals were already in existence in that ancient period with the exception of the vertebrates, the remains of which have apparently now been traced down to near the Cambrian level. In other words, at the stage where we first find evidence of living beings the series to which they belong had already climbed very far above the level of lifeless matter. ”

“ The very earliest existing fossils would lead us to believe, what is otherwise quite probable; that life on our planet began with very small forms—that it passed at first through a baby stage. The animals of the Cambrian period are almost all small mollusks, star-fishes, sponges, and other simple, primitive types of life. There were as yet no vertebrates of any sort, not even fishes, far less amphibians, reptiles, birds, or mammals. ”

“ In the same winding tract of Germany live the Cimbrians, close to the ocean; a community now very small, but great in fame. Nay, of their ancient renown, many and extensive are the traces and monuments still remaining; even their entrenchments upon either shore, so vast in compass that from thence you may even now measure the greatness and numerous bands of that people, and assent to the account of an army so mighty. It was on the six hundred and fortieth year of Rome, when of the arms of the Cimbrians the first mention was made, during the Consulship of Caecilius Metellus and Papirius Carbo. ”

“ The Cambrian period—General succession of Cambrian deposits in Wales—Lower Cambrian and Upper Cambrian—Cambrian deposits of the continent of Europe and North American—Life of the Cambrian period — Fucoids — Eophyton — Oldhamia — Sponges — Echinoderms — Annelides — Crustaceans — Structure of Trilobites—Brachiopods—Pteropods, Gasteropods, and Bivalves—Cephalopods—Literature. ”

“ If ye do this, the earth will bring forth fruit for you, and your wives will bear children, and your flocks will increase, and ye will be free men for all time. But if ye do not acquire the sovereignty again or attempt to recover it, I pray the gods that the opposite may happen to you all, and that every Persian may come to such an end as mine.' When Cambyses had thus spoken he lamented all the deeds that he had done, and the Persians rent their garments and lamented and cried aloud. ”