Sirach 16:30

This era witnesses the spread of life throughout the waters of the world; marine life has become well established on Urantia. The bottoms of the shallow and extensive inland seas are being gradually overrun by a profuse and luxuriant growth of vegetation, while the shore-line waters are swarming with the simple forms of animal life.

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.

As this era begins, the sea bottoms, the extensive continental shelves, and the numerous shallow near-shore basins are covered with prolific vegetation. The more simple and primitive forms of animal life have already developed from preceding vegetable organisms, and the early animal organisms have gradually made their way along the extensive coast lines of the various land masses until the many inland seas are teeming with primitive marine life. Since so few of these early organisms had shells, not many have been preserved as fossils. Nevertheless the stage is set for the opening chapters of that great “stone book” of the life-record preservation which was so methodically laid down during the succeeding ages.

And it was from such seashores of the mild and equable climes of a later age that primitive plant life found its way onto the land. There the high degree of carbon in the atmosphere afforded the new land varieties of life opportunity for speedy and luxuriant growth. Though this atmosphere was then ideal for plant growth, it contained such a high degree of carbon dioxide that no animal, much less man, could have lived on the face of the earth.

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.

We had planted the primitive form of marine life in the sheltered tropic bays of the central seas of the east-west cleavage of the breaking-up continental land mass. Our purpose in making three marine-life implantations was to insure that each great land mass would carry this life with it, in its warm-water seas, as the land subsequently separated. We foresaw that in the later era of the emergence of land life large oceans of water would separate these drifting continental land masses.

All of this story is graphically told within the fossil pages of the vast “stone book” of world record. And the pages of this gigantic biogeologic record unfailingly tell the truth if you but acquire skill in their interpretation. Many of these ancient sea beds are now elevated high upon land, and their deposits of age upon age tell the story of the life struggles of those early days. It is literally true, as your poet has said, “The dust we tread upon was once alive.”

By the dawn of this period of relative quiet on the earth’s surface, life is confined to the various inland seas and the oceanic shore line; as yet no form of land organism has evolved. Primitive marine animals are well established and are prepared for the next evolutionary development. Amebas are typical survivors of this initial stage of animal life, having made their appearance toward the close of the preceding transition period.

The vast group of rock systems which constituted the outer crust of the world during the life-dawn or Proterozoic era does not now appear at many points on the earth’s surface. And when it does emerge from below all the accumulations of subsequent ages, there will be found only the fossil remains of vegetable and early primitive animal life. Some of these older water-deposited rocks are commingled with subsequent layers, and sometimes they yield fossil remains of some of the earlier forms of vegetable life, while on the topmost layers occasionally may be found some of the more primitive forms of the early marine-animal organisms. In many places these oldest stratified rock layers, bearing the fossils of the early marine life, both animal and vegetable, may be found directly on top of the older undifferentiated stone.

Through almost endless cycles of gains and losses, adjustments and readjustments, all living organisms swing back and forth from age to age. Those that attain cosmic unity persist, while those that fall short of this goal cease to exist.