The Urantia Book

59. The Marine-Life Era on Urantia

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 Five million 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 500 to 5,000 feet 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 one thousand feet 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 one hundred feet thick, embracing more than two hundred 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 southeast 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 20,000 feet thick.

^59.4.9 250,000,000 years ago witnessed the appearance of the fish family, the vertebrates, one of the most important steps in all prehuman evolution.

^59.4.10 The arthropods, or crustaceans, were the ancestors of the first vertebrates. The forerunners of the fish family were two modified arthropod ancestors; one had a long body connecting a head and tail, while the other was a backboneless, jawless prefish. But these preliminary types were quickly destroyed when the fishes, the first vertebrates of the animal world, made their sudden appearance from the north.

^59.4.11 Many of the largest true fish belong to this age, some of the teeth-bearing varieties being twenty-five to thirty feet long; the present-day sharks are the survivors of these ancient fishes. The lung and armored fishes reached their evolutionary apex, and before this epoch had ended, fishes had adapted to both fresh and salt waters.

^59.4.12 Veritable bone beds of fish teeth and skeletons may be found in the deposits laid down toward the close of this period, and rich fossil beds are situated along the coast of California since many sheltered bays of the Pacific Ocean extended into the land of that region.

^59.4.13 The earth was being rapidly overrun by the new orders of land vegetation. Heretofore few plants grew on land except about the water's edge. Now, and suddenly, the prolific fern family appeared and quickly spread over the face of the rapidly rising land in all parts of the world. Tree types, two feet thick and forty feet high, soon developed; later on, leaves evolved, but these early varieties had only rudimentary foliage. There were many smaller plants, but their fossils are not found since they were usually destroyed by the still earlier appearing bacteria.

^59.4.14 As the land rose, North America became connected with Europe by land bridges extending to Greenland. And today Greenland holds the remains of these early land plants beneath its mantle of ice.

^59.4.15 240,000,000 years ago the land over parts of both Europe and North and South America began to sink. This subsidence marked the appearance of the last and least extensive of the Devonian floods. The arctic seas again moved southward over much of North America, the Atlantic inundated a large part of Europe and western Asia, while the southern Pacific covered most of India. This inundation was slow in appearing and equally slow in retreating. The Catskill Mountains along the west bank of the Hudson River are one of the largest geologic monuments of this epoch to be found on the surface of North America.

^59.4.16 230,000,000 years ago the seas were continuing their retreat. Much of North America was above water, and great volcanic activity occurred in the St. Lawrence region. Mount Royal, at Montreal, is the eroded neck of one of these volcanoes. The deposits of this entire epoch are well shown in the Appalachian Mountains of North America where the Susquehanna River has cut a valley exposing these successive layers, which attained a thickness of over 13,000 feet.

^59.4.17 The elevation of the continents proceeded, and the atmosphere was becoming enriched with oxygen. The earth was overspread by vast forests of ferns one hundred feet high and by the peculiar trees of those days, silent forests; not a sound was heard, not even the rustle of a leaf, for such trees had no leaves.

^59.4.18 And thus drew to a close one of the longest periods of marine-life evolution, the age of fishes. This period of the world's history lasted almost fifty million years; it has become known to your researchers as the Devonian.

5. The Crustal-Shifting Stage
The Fern-Forest Carboniferous Period
The Age of Frogs

^59.5.1 The appearance of fish during the preceding period marks the apex of marine-life evolution. From this point onward the evolution of land life becomes increasingly important. And this period opens with the stage almost ideally set for the appearance of the first land animals.

^59.5.2 220,000,000 years ago many of the continental land areas, including most of North America, were above water. The land was overrun by luxurious vegetation; this was indeed the age of ferns. Carbon dioxide was still present in the atmosphere but in lessening degree.

^59.5.3 Shortly thereafter the central portion of North America was inundated, creating two great inland seas. Both the Atlantic and Pacific coastal highlands were situated just beyond the present shore lines. These two seas presently united, commingling their different forms of life, and the union of these marine fauna marked the beginning of the rapid and world-wide decline in marine life and the opening of the subsequent land-life period.

^59.5.4 210,000,000 years ago the warm-water arctic seas covered most of North America and Europe. The south polar waters inundated South America and Australia, while both Africa and Asia were highly elevated.

^59.5.5 When the seas were at their height, a new evolutionary development suddenly occurred. Abruptly, the first of the land animals appeared. There were numerous species of these animals that were able to live on land or in water. These air-breathing amphibians developed from the arthropods, whose swim bladders had evolved into lungs.

^59.5.6 From the briny waters of the seas there crawled out upon the land snails, scorpions, and frogs. Today frogs still lay their eggs in water, and their young first exist as little fishes, tadpoles. This period could well be known as the age of frogs.

^59.5.7 Very soon thereafter the insects first appeared and, together with spiders, scorpions, cockroaches, crickets, and locusts, soon overspread the continents of the world. Dragon flies measured thirty inches across. One thousand species of cockroaches developed, and some grew to be four inches long.

^59.5.8 Two groups of echinoderms became especially well developed, and they are in reality the guide fossils of this epoch. The large shell-feeding sharks were also highly evolved, and for more than five million years they dominated the oceans. The climate was still mild and equable; the marine life was little changed. Fresh-water fish were developing and the trilobites were nearing extinction. Corals were scarce, and much of the limestone was being made by the crinoids. The finer building limestones were laid down during this epoch.

^59.5.9 The waters of many of the inland seas were so heavily charged with lime and other minerals as greatly to interfere with the progress and development of many marine species. Eventually the seas cleared up as the result of an extensive stone deposit, in some places containing zinc and lead.

^59.5.10 The deposits of this early Carboniferous age are from 500 to 2,000 feet thick, consisting of sandstone, shale, and limestone. The oldest strata yield the fossils of both land and marine animals and plants, along with much gravel and basin sediments. Little workable coal is found in these older strata. These depositions throughout Europe are very similar to those laid down over North America.

^59.5.11 Toward the close of this epoch the land of North America began to rise. There was a short interruption, and the sea returned to cover about half of its previous beds. This was a short inundation, and most of the land was soon well above water. South America was still connected with Europe by way of Africa.

^59.5.12 This epoch witnessed the beginning of the Vosges, Black Forest, and Ural mountains. Stumps of other and older mountains are to be found all over Great Britain and Europe.

^59.5.13 200,000,000 years ago the really active stages of the Carboniferous period began. For twenty million years prior to this time the earlier coal deposits were being laid down, but now the more extensive coal-formation activities were in process. The length of the actual coal-deposition epoch was a little over twenty-five million years.

^59.5.14 The land was periodically going up and down due to the shifting sea level occasioned by activities on the ocean bottoms. This crustal uneasiness - the settling and rising of the land - in connection with the prolific vegetation of the coastal swamps, contributed to the production of extensive coal deposits, which have caused this period to be known as the Carboniferous. And the climate was still mild the world over.

^59.5.15 The coal layers alternate with shale, stone, and conglomerate. These coal beds over central and eastern United States vary in thickness from forty to fifty feet. But many of these deposits were washed away during subsequent land elevations. In some parts of North America and Europe the coal-bearing strata are 18,000 feet in thickness.

^59.5.16 The presence of roots of trees as they grew in the clay underlying the present coal beds demonstrates that coal was formed exactly where it is now found. Coal is the water-preserved and pressure-modified remains of the rank vegetation growing in the bogs and on the swamp shores of this faraway age. Coal layers often hold both gas and oil. Peat beds, the remains of past vegetable growth, would be converted into a type of coal if subjected to proper pressure and heat. Anthracite has been subjected to more pressure and heat than other coal.

^59.5.17 In North America the layers of coal in the various beds, which indicate the number of times the land fell and rose, vary from ten in Illinois, twenty in Pennsylvania, thirty-five in Alabama, to seventy-five in Canada. Both fresh- and salt-water fossils are found in the coal beds.

^59.5.18 Throughout this epoch the mountains of North and South America were active, both the Andes and the southern ancestral Rocky Mountains rising. The great Atlantic and Pacific high coastal regions began to sink, eventually becoming so eroded and submerged that the coast lines of both oceans withdrew to approximately their present positions. The deposits of this inundation average about one thousand feet in thickness.

^59.5.19 190,000,000 years ago witnessed a westward extension of the North American Carboniferous sea over the present Rocky Mountain region, with an outlet to the Pacific Ocean through northern California. Coal continued to be laid down throughout the Americas and Europe, layer upon layer, as the coastlands rose and fell during these ages of seashore oscillations.

^59.5.20 180,000,000 years ago brought the close of the Carboniferous period, during which coal had been formed all over the world - in Europe, India, China, North Africa, and the Americas. At the close of the coal-formation period North America east of the Mississippi valley rose, and most of this section has ever since remained above the sea. This land-elevation period marks the beginning of the modern mountains of North America, both in the Appalachian regions and in the west. Volcanoes were active in Alaska and California and in the mountain-forming regions of Europe and Asia. Eastern America and western Europe were connected by the continent of Greenland.

^59.5.21 Land elevation began to modify the marine climate of the preceding ages and to substitute therefor the beginnings of the less mild and more variable continental climate.

^59.5.22 The plants of these times were spore bearing, and the wind was able to spread them far and wide. The trunks of the Carboniferous trees were commonly seven feet in diameter and often one hundred and twenty-five feet high. The modern ferns are truly relics of these bygone ages.

^59.5.23 In general, these were the epochs of development for fresh-water organisms; little change occurred in the previous marine life. But the important characteristic of this period was the sudden appearance of the frogs and their many cousins. The life features of the coal age were ferns and frogs.

6. The Climatic Transition Stage
The Seed-Plant Period
The Age of Biologic Tribulation

^59.6.1 This period marks the end of pivotal evolutionary development in marine life and the opening of the transition period leading to the subsequent ages of land animals.

^59.6.2 This age was one of great life impoverishment. Thousands of marine species perished, and life was hardly yet established on land. This was a time of biologic tribulation, the age when life nearly vanished from the face of the earth and from the depths of the oceans. Toward the close of the long marine-life era there were more than one hundred thousand species of living things on earth. At the close of this period of transition less than five hundred had survived.

^59.6.3 The peculiarities of this new period were not due so much to the cooling of the earth's crust or to the long absence of volcanic action as to an unusual combination of commonplace and pre-existing influences - restrictions of the seas and increasing elevation of enormous land masses. The mild marine climate of former times was disappearing, and the harsher continental type of weather was fast developing.

^59.6.4 170,000,000 years ago great evolutionary changes and adjustments were taking place over the entire face of the earth. Land was rising all over the world as the ocean beds were sinking. Isolated mountain ridges appeared. The eastern part of North America was high above the sea; the west was slowly rising. The continents were covered by great and small salt lakes and numerous inland seas which were connected with the oceans by narrow straits. The strata of this transition period vary in thickness from 1,000 to 7,000 feet.

^59.6.5 The earth's crust folded extensively during these land elevations. This was a time of continental emergence except for the disappearance of certain land bridges, including the continents which had so long connected South America with Africa and North America with Europe.

^59.6.6 Gradually the inland lakes and seas were drying up all over the world. Isolated mountain and regional glaciers began to appear, especially over the Southern Hemisphere, and in many regions the glacial deposit of these local ice formations may be found even among some of the upper and later coal deposits. Two new climatic factors appeared - glaciation and aridity. Many of the earth's higher regions had become arid and barren.

^59.6.7 Throughout these times of climatic change, great variations also occurred in the land plants. The seed plants first appeared, and they afforded a better food supply for the subsequently increased land-animal life. The insects underwent a radical change. The resting stages evolved to meet the demands of suspended animation during winter and drought.

^59.6.8 Among the land animals the frogs reached their climax in the preceding age and rapidly declined, but they survived because they could long live even in the drying-up pools and ponds of these far-distant and extremely trying times. During this declining frog age, in Africa, the first step in the evolution of the frog into the reptile occurred. And since the land masses were still connected, this prereptilian creature, an air breather, spread over all the world. By this time the atmosphere had been so changed that it served admirably to support animal respiration. It was soon after the arrival of these prereptilian frogs that North America was temporarily isolated, cut off from Europe, Asia, and South America.

^59.6.9 The gradual cooling of the ocean waters contributed much to the destruction of oceanic life. The marine animals of those ages took temporary refuge in three favorable retreats: the present Gulf of Mexico region, the Ganges Bay of India, and the Sicilian Bay of the Mediterranean basin. And it was from these three regions that the new marine species, born to adversity, later went forth to replenish the seas.

^59.6.10 160,000,000 years ago the land was largely covered with vegetation adapted to support land-animal life, and the atmosphere had become ideal for animal respiration. Thus ends the period of marine-life curtailment and those testing times of biologic adversity which eliminated all forms of life except such as had survival value, and which were therefore entitled to function as the ancestors of the more rapidly developing and highly differentiated life of the ensuing ages of planetary evolution.

^59.6.11 The ending of this period of biologic tribulation, known to your students as the Permian, also marks the end of the long Paleozoic era, which covers one quarter of the planetary history, two hundred and fifty million years.

^59.6.12 The vast oceanic nursery of life on Urantia has served its purpose. During the long ages when the land was unsuited to support life, before the atmosphere contained sufficient oxygen to sustain the higher land animals, the sea mothered and nurtured the early life of the realm. Now the biologic importance of the sea progressively diminishes as the second stage of evolution begins to unfold on the land.

^59.6.13 [Presented by a Life Carrier of Nebadon, one of the original corps assigned to Urantia.]