Mystic Period.—The Mystic period in paleontology begins with the Greeks, five centuries before the present era, and continues down to the beginning of the seventeenth century of our time. Some correctly saw that the fossils were once living marine animals, and that the sea had been where they now occur. Others interpreted fossil mammal bones as those of human giants, the Titans, but the Aristotelian view that they were of spontaneous generation through the hidden forces of the earth dominated all thought for about twenty centuries.
In the sixteenth century canals were being dug in Northern Italy, and the many fossils so revealed led to a fierce discussion as to their actual nature. Leonardo da Vinci (1452–1519) opposed the commonly accepted view of their spontaneous generation and said that they were the remains of once living animals and that the sea had been where they occur. “You tell me,” he said, “that Nature and the influence of the stars have formed these shells in the mountains; then show me a place in the mountains where the stars at the present day make shelly forms of different ages, and of different species in the same place.” However, nothing came of his teachings and those of his countryman Fracastorio (1483–1553), who further ridiculed the idea that they were the remains of the deluge. The first mineralogist, Agricola, described them as minerals—fossilia—and said that they arose in the ground from fatty matter set in fermentation by heat. Others said that they were freaks of nature. Martin Lister (1638–1711) figured fossils side by side with living shells to show that they were extinct forms of life. In the seventeenth century, and especially in Italy and Germany, many books were published on fossils, some with illustrations so accurate that the species can be recognized to-day. Finally, toward the close of this century the influence of Aristotle and the scholastic tendency to disputation came more or less to an end. Fossils were already to many naturalists once living plants and animals. Marsh states: “The many collections of fossils that had been brought together, and the illustrated works that had been published about them, were a foundation for greater progress, and, with the eighteenth century, the second period in the history of paleontology began.”
Diluvial Period.—During the eighteenth century many more books on fossils were published in western Europe, and now the prevalent explanation was that they were the remains of the Noachian deluge. For nearly a century theologians and laymen alike took this view, and some of the books have become famous on this account, but the diluvial views sensibly declined with the close of the eighteenth century.
The true nature of fossils had now been clearly determined. They were the remains of plants and animals, deposited long before the deluge, part in fresh water and part in the sea. “Some indicated a mild climate, and some the tropics. That any of these were extinct species, was as yet only suspected.” Yet before the close of the century there were men in England and France who pointed out that different formations had different fossils and that some of them were extinct. These views then led to many fantastic theories as to how the earth was formed—dreams, most of them have been called. Marsh says:
“The dominant idea of the first sixteen centuries of the present era was, that the universe was made for Man. This was the great obstacle to the correct determination of the position of the earth in the universe, and, later, of the age of the earth.... In a superstitious age, when every natural event is referred to a supernatural cause, science cannot live.... Scarcely less fatal to the growth of science is the age of Authority, as the past proves too well. With freedom of thought, came definite knowledge, and certain progress;—but two thousand years was long to wait.”
One of the most significant publications of this period was Linnæus’s Systema Naturæ, which appeared in 1735. In this work was introduced binomial nomenclature, or the system of giving each plant and animal species a generic and specific name, as Felis leo for the lion. The system was, however, not established until the tenth edition of the work in 1758, which became the starting point of zoological nomenclature. Since then there has been added another canon, the law of priority, which holds that the first name applied to a given form shall stand against all later names given to the same organism.
Catastrophic Period.—With the beginning of the nineteenth century there started a new era in paleontology, and this was the time when the foundations of the science were laid. The period continued for six decades, or until the time of the Origin of Species. Marsh says that now “method replaced disorder, and systematic study superseded casual observation.” Fossils were accurately determined, comparisons were made with living forms, and the species named according to the binomial system. However, every species, recent and extinct, was regarded as a separate creation, and because of the usually sharp separation of the superposed fossil faunas and floras, these were held to have been destroyed through a series of periodic catastrophes of which the Noachian deluge was the last.
Lamarck between 1802 and 1806 described the Tertiary shells of the Paris basin. Comparing them with the living forms, he saw that most of the fossils were of extinct species, and in this way he came to be the founder of modern invertebrate paleontology. He also maintained after 1801 that life has been continuous since its origin and that nature has been uniform in the course of its development. Marsh adds:
“His researches on the invertebrate fossils of the Paris Basin, although less striking, were not less important than those of Cuvier on the vertebrates; while the conclusions he derived from them form the basis of modern biology.”
“Lamarck was the prophetic genius, half a century in advance of his time.”