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Summary:
The Cambrian period - the era of the trilobites
400,000,000 years ago, both plant and animal marine life successfully spread around the world. The world's climate has become slightly warmer and more uniform. A general submergence was taking place on the sea-coasts of the various continents, especially North and South America. New oceans appeared and older bodies of water greatly expanded.
380,000,000 years ago, Asia began to rise, and the other continents rose briefly. But as this era progressed, the newly forming Atlantic Ocean made deep inroads into all adjacent coastlines. The North Atlantic or Arctic seas at that time joined the waters of the Gulf of Mexico.
370,000,000 years ago there was an extensive and almost complete submergence of North and South America, after which Africa and Australia went under water. Only parts of North America remained above the level of these shallow Cambrian seas. After 5,000,000 years the seas gave way to the rising land.
360,000,000 years ago, land growth continued. North and South America rose to a considerable height. Western Europe and the British Isles surfaced, except for parts of Wales which were deep under water. During these epochs, large glaciers were absent.
Ordovician period - continental warming - era of invertebrate animals
350,000,000 years ago began the period of great submergence of all continents except Central Asia. The landmasses repeatedly went under the water; only the coastal elevations remained above these shallow but vast and shifting inland seas. This period was characterized by three great floods, but even before its end the continents rose again, in which the total surface of the land exceeded by fifteen percent that which exists today. The Caribbean region rose to a great height.
340,000,000 years ago there was another extensive submergence of the land, which affected not only Asia and Australia. The waters of the oceans everywhere mingled. This was the Great Limestone Period, in which much of this stone was deposited by lime-releasing algae.
330,000,000 years ago, the entire world began a period of relative stability in which a significant part of the land was above the surface of the water.
320,000,000 years ago was the third great flood of this period. The water covered the entire surface of the land submerged during the previous flood.
By 310,000,000 years ago, land again rose to a considerable height throughout the world, except for the southern parts of North America. Mexico floated away, resulting in the formation of the Gulf of Mexico, which has retained its current shape to this day.
Silurian Period - Second Great Submergence Period - Coral Period - Brachiopod Era
300,000,000 years ago another prolonged period of land submergence began. The encroachment of the ancient Silurian seas in a southerly and northerly direction resulted in the absorption of most of Europe and North America. The land was not much above sea level, so there were no numerous coastal deposits. The seas abounded with creatures with calcareous shells, and the deposition of these shells on the sea floor gradually formed vast deposits of limestone.
By 290,000,000 years ago, the sea had largely retreated from the continents and the floors of the surrounding oceans were subsiding. The Himalayas of Asia rose, and the vast Caledonian Mountains, stretching from Ireland through Scotland and on to Svalbard.
280,000,000 years ago, much of the continents rose after the second Silurian flood. The rock deposits associated with this submergence are known in North America as the "Niagara Limestone". This layer of rock extends from the eastern mountains to the valleys of the Mississippi River, but continues westward only in the southern valley.
The Devonian period – era of the great uplift of land – period of plant life on earth – age of fishes
270,000,000 years ago the continents were entirely above sea level. It was the first time in many millions of years that such an amount of land had been above water at the same time; it was one of the greatest eras of drought growth.
260,000,000 years ago, toward the end of this great period of land depression, North America was partially covered by seas that simultaneously joined Pacific, Atlantic, and Arctic waters in the Gulf of Mexico.
250,000,000 years ago, fish appeared - the vertebrates that became one of the most important stages of evolution until the appearance of man.
240,000,000 years ago, parts of the land in Europe, North and South America began to sink. This subsidence marked the beginning of the last and least extensive of the Devonian floods.
230,000,000 years ago, the seas continued to recede. Vast areas of North America were above sea level and there was powerful volcanic activity in the area of the St. Lawrence River. Mount Royal, near Montreal, is the eroded neck of one of these volcanoes.
Carboniferous period - periodic shifting of the crust - age of frogs
220,000,000 years ago, many areas of the continental landmass, including much of North America, were above water level. The earth became covered with luxuriant vegetation; the age of ferns came.
210,000,000 years ago, warm arctic seas hid much of North America and Europe. Southern polar waters warmed South America and Australia, while both Africa and Asia were at a considerable height above sea level.
200,000,000 years ago, really active stages of the Carboniferous period began to operate. The early coal deposits had formed during the twenty million years preceding this time, but coal formation was now occurring on a wider scale.
190,000,000 years ago, a westward expansion of the sea that existed in the Carboniferous period on the territory of North America began; this sea submerged the present-day Rocky Mountain region and formed an outlet to the Pacific Ocean through northern California.
180,000,000 years ago, the coal period ended, during which coal was formed all over the world - in Europe, India, China, North Africa and the Americas.
The Permian period - a transitional climatic period - the period of seed plants - an era of biological upheaval
170,000,000 years ago, evolutionary changes and adaptations covered the entire surface of the Earth. All over the world the land was rising and the ocean floor was sinking. Isolated mountain ridges appeared.
This was the time of the emergence of the continents, except for the disappearance of certain land bridges, including the continents that had so long connected South America to Africa and North America to Europe.
Inland lakes and seas gradually dried up around the world. Separate mountain and regional glaciers began to appear, especially in the southern hemisphere, and in many areas ice deposits resulting from these local ice formations can even be met with among some surface and later coal deposits.
160,000,000 years ago - end of the Permian period of the Paleozoic era
The vast ocean cradle of life on Urantia has fulfilled its purpose. In the course of long ages, when the earth was not adapted to the support of life—until the atmosphere became sufficiently saturated with oxygen to sustain the life of the higher land animals—the sea cared for and nourished the ancient life of this world. From this point on, the biological importance of the sea gradually declined, until the second stage of evolution began to unfold on land.