^59:3.2 No fire rocks or lava are found in the stone layers of this period except those of the great volcanoes of southern Europe and eastern Maine and the lava flows of Quebec. Volcanic action was largely past. This was the height of great water deposition; there was little or no mountain building.

^59:3.3 ¶ 290,000,000 years ago the sea had largely withdrawn from the continents, and the bottoms of the surrounding oceans were sinking. The land masses were little changed until they were again submerged. The early mountain movements of all the continents were beginning, and the greatest of these crustal upheavals were the Himalayas of Asia and the great Caledonian Mountains, extending from Ireland through Scotland and on to Spitzbergen.

^59:3.4 It is in the deposits of this age that much of the gas, oil, zinc, and lead are found, the gas and oil being derived from the enormous collections of vegetable and animal matter carried down at the time of the previous land submergence, while the mineral deposits represent the sedimentation of sluggish bodies of water. Many of the rock salt deposits belong to this period.

^59:3.5 The trilobites rapidly declined, and the centre of the stage was occupied by the larger molluscs, or cephalopods. These animals grew to be 4.6 m long and 30 cm in diameter and became masters of the seas. This species of animal appeared suddenly and assumed dominance of sea life.

^59:3.6 The great volcanic activity of this age was in the European sector. Not in millions upon millions of years had such violent and extensive volcanic eruptions occurred as now took place around the Mediterranean trough and especially in the neighbourhood of the British Isles. This lava flow over the British Isles region today appears as alternate layers of lava and rock 7,600 m thick. These rocks were laid down by the intermittent lava flows which spread out over a shallow sea bed, thus interspersing the rock deposits, and all of this was subsequently elevated high above the sea. Violent earthquakes took place in northern Europe, notably in Scotland.

^59:3.7 The oceanic climate remained mild and uniform, and the warm seas bathed the shores of the polar lands. Brachiopod and other marine-life fossils may be found in these deposits right up to the North Pole. Gastropods, brachiopods, sponges, and reef-making corals continued to increase.

^59:3.8 The close of this epoch witnesses the second advance of the Silurian seas with another commingling of the waters of the southern and northern oceans. The cephalopods dominate marine life, while associated forms of life progressively develop and differentiate.

^59:3.9 ¶ 280,000,000 years ago the continents had largely emerged from the second Silurian inundation. The rock deposits of this submergence are known in North America as Niagara limestone because this is the stratum of rock over which Niagara Falls now flows. This layer of rock extends from the eastern mountains to the Mississippi valley region but not farther west except to the south. Several layers extend over Canada, portions of South America, Australia, and most of Europe, the average thickness of this Niagara series being about 183 m. Immediately overlying the Niagara deposit, in many regions may be found a collection of conglomerate, shale, and rock salt. This is the accumulation of secondary subsidences. This salt settled in great lagoons which were alternately opened up to the sea and then cut off so that evaporation occurred with deposition of salt along with other matter held in solution. In some regions these rock salt beds are 20 m thick.

^59:3.10 The climate is even and mild, and marine fossils are laid down in the arctic regions. But by the end of this epoch the seas are so excessively salty that little life survives.

^59:3.11 Toward the close of the final Silurian submergence there is a great increase in the echinoderms — the stone lilies — as is evidenced by the crinoid limestone deposits. The trilobites have nearly disappeared, and the molluscs continue monarchs of the seas; coral-reef formation increases greatly. During this age, in the more favourable locations the primitive water scorpions first evolve. Soon thereafter, and suddenly, the true scorpions — actual air breathers — make their appearance.

^59:3.12 These developments terminate the 3^rd marine-life period, covering 25,000,000 years and known to your researchers as the Silurian.

4. THE GREAT LAND-EMERGENCE STAGE

THE VEGETATIVE LAND-LIFE PERIOD

THE AGE OF FISHES

^59:4.1 In the agelong struggle between land and water, for long periods the sea has been comparatively victorious, but times of land victory are just ahead. And the continental drifts have not proceeded so far but that, at times, practically all of the land of the world is connected by slender isthmuses and narrow land bridges.

^59:4.2 As the land emerges from the last Silurian inundation, an important period in world development and life evolution comes to an end. It is the dawn of a new age on earth. The naked and unattractive landscape of former times is becoming clothed with luxuriant verdure, and the first magnificent forests will soon appear.

^59:4.3 The marine life of this age was very diverse due to the early species segregation, but later on there was free commingling and association of all these different types. The brachiopods early reached their climax, being succeeded by the arthropods, and barnacles made their first appearance. But the greatest event of all was the sudden appearance of the fish family. This became the age of fishes, that period of the world’s history characterized by the vertebrate type of animal.

^59:4.4 ¶ 270,000,000 years ago the continents were all above water. In millions upon millions of years not so much land had been above water at one time; it was one of the greatest land-emergence epochs in all world history.

^59:4.5 5,000,000 years later the land areas of North and South America, Europe, Africa, northern Asia, and Australia were briefly inundated, in North America the submergence at one time or another being almost complete; and the resulting limestone layers run from 150 to 1,500 m in thickness. These various Devonian seas extended first in one direction and then in another so that the immense arctic North American inland sea found an outlet to the Pacific Ocean through northern California.

^59:4.6 ¶ 260,000,000 years ago, toward the end of this land-depression epoch, North America was partially overspread by seas having simultaneous connection with the Pacific, Atlantic, Arctic, and Gulf waters. The deposits of these later stages of the first Devonian flood average about 300 m in thickness. The coral reefs characterizing these times indicate that the inland seas were clear and shallow. Such coral deposits are exposed in the banks of the Ohio River near Louisville, Kentucky, and are about 30 m thick, embracing more than 200 varieties. These coral formations extend through Canada and northern Europe to the arctic regions.

^59:4.7 Following these submergences, many of the shore lines were considerably elevated so that the earlier deposits were covered by mud or shale. There is also a red sandstone stratum which characterizes one of the Devonian sedimentations, and this red layer extends over much of the earth’s surface, being found in North and South America, Europe, Russia, China, Africa, and Australia. Such red deposits are suggestive of arid or semiarid conditions, but the climate of this epoch was still mild and even.

^59:4.8 Throughout all of this period the land south-east of the Cincinnati Island remained well above water. But very much of western Europe, including the British Isles, was submerged. In Wales, Germany, and other places in Europe the Devonian rocks are 6,100 m thick.