The plant organizes its substance directly from the crude, unorganized material of the earth; but the animal depends on the plant world as its magazine of food. It uses only organized material-plants or other animals.

Thus the two kingdoms differ widely while being most intimately bound together.

CHAPTER V.

VEGETATION IN THE VALLEY, ANCIENT AND MODERN.

The system of life has two sides, the vegetable and the animal, which interlock to form a whole. In some respects, also, the system of vegetable life may be considered the base or condition of animal life. The building force goes directly to the mineral kingdom for its material when it constructs vegetable forms. Decayed vegetable or animal remains, indeed, speed its work, but only by furnishing the material required in greater abundance, thereby saving time and enabling it to build more sumptuously. Though the general plan is the same, the ends are different in each of the two systems. For the vegetable the aim is restricted and modest. It is the servant to wait upon the animal, the magazine containing the supplies for its physical wants.

This is the leading use of vegetable life, but various others are seen, in all of which service is rendered to.the higher class. It aids in the collection and deposition of some metals very useful to man; it supplies petroleum and coal in vast abundance; it furnishes numberless materials for man's higher development; enriches the surface of the earth by the decay of its forms and covers it with beauty; supplies the most agreeable and nourishing fruits, and is a magazine of perfumes, of medicines and of art supplies. Much of this, however, was reserved for development as the human period approached. In the early days of Paleozoic time the builder employed comparatively little skill on vegetable forms.

The general plan of vegetable structures is radiate; that is, similar parts start from a common center, and spread out in various directions, while for animals there are five different

plans by which the life forms of that kingdom are graded. There are, however, two great classes of vegetable formsCryptogams and Phenogams-the distinction being founded on their modes of reproduction. Cryptogams have no proper flowers or fruit, the seed which produces the new plant being of the simplest kind, and, for the most part, there is very little of the surprisingly elaborate and ingenious detail found, as a rule, in the higher class.

Phenogams have flowers which surround a system of organs employed in producing the seed that is to give birth to the young plant, and the seed is commonly furnished with a store of nutriment for the use of the germ in the early stages of its development. It is the parental instinct caring for the start in life of its offspring. Very often this thoughtful provision is of the greatest advantage to man. All the grains that furnish him with the "staff of life" are composed of this concentrated food for the young plant stored in the seed.

It seems entirely probable that vegetable life was introduced before any animal forms appeared, although geologists have not yet been able to prove positively that it was so. For a large part of the ancient time no plants are known to have grown on the land, only sea weeds having been preserved. Plants separate, concentrate, and store up in their forms the nutriment required by the animal, and probably the simplest possible vegetable growth had supplied a sufficient quantity of this in the waters when the first animals appeared. It was only in later times, after vast masses of rock formations had somewhat cleared the waters of their excessive chemical solutions, that vegetable substances became sufficiently firm to be preserved in the forming rock of their times.

Recently there have been found various and significant traces of vegetation in the Azoic rocks. The presence of carbon in various forms is believed to have originated in large part from vegetable growth, and the deposit of vast quantities of iron ore along the southern border of the most ancient land is by

THE PROGRESS OF VEGETABLE LIFE.

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some considered due to the vegetation of the marshes of that time, the vegetable infusion in the water precipitating the iron oxyds washed down from the neighboring rocks. When the conditions suitable for sea weeds had been reached, the warm and shallow seas probably produced an extremely abundant growth and served to nourish the immense swarms of the lower forms of animal life which are known to have existed in the early part of Palæozoic Time.

Much the larger part of ancient time had passed away before the rocks began to record the existence of land plants. The first that has been satisfactorily distinguished as such was a species of gigantic club moss. It is probable that many varieties of lichens and mosses had long before flourished and laid the foundation for the extremely profuse vegetation that now hastened to make ready for the era of coal. The evidence seems to prove that the higher lands were not in a condition to support a profuse vegetation, and that trees and plants mostly grew in marshes or very near the surface of the water.

Many of the plants that are dwarfed in our age were then of great size. A large proportion of the coal was made from ferns and kindred plants, almost all being from the class of Cryptogams, of loose structure and rapid growth. The climate appears to have been about the same over all the globe, for the coal beds of every country made in the great coal period show that they were produced by exactly the same kind of forests. The temperature was evidently much like that of the Torrid Zone of our day, and there seems to have been a larger proportion of carbonic acid gas in the composition of the air, which would be sufficient of itself to increase the rapidity and luxuriance of vegetable growth. It was this extra carbon that was now removed to be stored up in the earth for future use.

The mountains of that time were few and of no great height, and the regions producing coal were low and marshy. The conditions were therefore favorable for the rapid produc

tion of the immense woody growth that has produced the hundred and fifty thousand square miles of workable coal in the United States-almost all of which is in, or near the borders of, the Mississippi Basin. From near the Atlantic shore to the Mississippi River, and some hundreds of miles beyond, was a vast marshy level directly across the Northern and Central Valley, and across Eastern Tennessee into Middle Alabama. There were numerous shallow lakes and sluggish streams flowing mainly from the north or northeast. shallow water gradually changed to marsh, and impenetrable jungles covered the country; a heavy, hot, stifling air brooded over the whole, and a dense mass of forest and marsh vegetation, of which the human period gives no example, accumulated the material for the coal-beds.

The

This region was immersed under water and raised again a multitude of times-in some places at least a hundred. A small change of level and a sudden flood from higher ground would sweep all this dense mass into heaps and cover it with water and mud before it could decay. The great feature of this age of the world, which must have lasted a very long time, was the vegetation and its sudden burial so many times in succession. Had there been a human being present to note this splendor of development in the plant world and its repeated ruin, it must have seemed an utter confusion and waste. If this material, however, had not been so stored up, one of the principal means of human discipline and development would have failed in our century and the times to come, and the fate of mankind would have been greatly changed.

Previous to the coal-making period in the last part of the Palæozoic, or ancient time, the first representatives of the second and higher order of vegetable forms appeared. The Phenogams were first represented by a tree belonging to the Conifer tribe, which includes the pine and other cone-bearing trees, and they flourished to a considerable extent during the coal-making era. Another class, somewhat resembling the