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 10 in Illinois, 20 in Pennsylvania, 35 in Alabama, to 75 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 300 m in thickness.
59:5.19 ¶
59:5.20 ¶
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 2 m in diameter and often 38 m 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
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 100,000 species of living things on earth. At the close of this period of transition less than 500 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 ¶
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
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 favourable 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 ¶
59:6.11 The ending of this period of biologic tribulation, known to your students as the
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.]
PAPER № 60
URANTIA DURING THE EARLY LAND-LIFE ERA
