LESSON V.

THE PALM AND THE MAN.

“So careful of the type she seems,So careless of the single life.‘So careful of the type?’ but no,From scarped cliff and quarried stoneShe cries, ‘A thousand types are gone,I care for nothing, all shall go!’”

“So careful of the type she seems,So careless of the single life.

“So careful of the type she seems,

So careless of the single life.

‘So careful of the type?’ but no,From scarped cliff and quarried stoneShe cries, ‘A thousand types are gone,I care for nothing, all shall go!’”

‘So careful of the type?’ but no,

From scarped cliff and quarried stone

She cries, ‘A thousand types are gone,

I care for nothing, all shall go!’”

—Tennyson,In Memoriam.

READY FOR MAN.

What have we thus far found to be the processes of earth-building? First, rocky crust uplifted into mountain ridges. Then deposit of sediment by the waters until islands and continents capable of maintaining animal and vegetable life are formed. Ages of increase and successive growth follow; thensinking of the earth-crust, accompanied by earthquakes and volcanoes; after this, fresh upheaval. With these surface changes come changes in the plant and animal life, especially in the former; for plants seem not to have the happy faculty of animals in accommodating themselves to new conditions. With the changing ages some animals entirely disappear, and are known to us only by their fossil remains. Others are modified and fitted to their new home.

We must observe that in no period of sinking after the first land age was the land all covered by water, nor were all the living things of any period destroyed. There has been a continuance of animal life on the globe from the first earth-building time until now. The Permian and Chalk ages were probably the periods of greatest changes. During the Chalk age certain of the later forms of life appeared. The fruit trees, and all the highest and most choice forms of vegetable life, were present among the plants. Fishes and reptiles, crabs and lobsters like those which now live, and the first specimens of the great Order of the Mammals, were found in the troubled seas of the Chalk age. It was with plants that are called exogens or outside growers, having two seed-leaves,[14]such as our fruit trees, and the oaks, maples, chestnuts, and elms, that modern plant life began. When the mammalians came, they were the advance guard of the higher class of animal life. This class of mammalia includes all animals which have young which are nourished with milk by their mothers.

The first age of the Neozoic, or New Life period, ismarked by a certain singular kind of limestone rock, called nummulite or money-stone. The stone receives this odd name from a great variety of flat shells which fill the rock, and have been fancied to resemble pennies, shillings, and sixpences. These nummulite shells are very curious; some are so small that you can scarcely see them without a microscope; others are as broad as the above-named coins. Each shell is made up of a great number of little cells, set in rings, beginning with a very small ring about the central cell, and the next a little larger, and so on. The shells were the homes of creatures called foraminifera, some of which are now living and building shells in the bottom of our seas.

When these creatures were alive these cells were filled with a soft substance such as we see in jelly-fish.[15]We can scarcely realize the vast amount of work done by these small, feeble creatures, in earth-building. The nummulites were the stonemasons of continents. The nummulite sandstone is found in beds, sometimes thousands of feet thick. Imagination fails to compass the multitudes of tiny living creatures which piled up ten thousand feet of the Swiss Alps, and built the snowy peaks of distant Thibet, and grain by grain laid up the long chains of the Pyrenees.

Little microscopic creatures, close kin to these nummulites, built the rocks in Egypt of which the Sphinx and Pyramids are made, and the enormous platform upon which they stand. These little animals also laid up the vast beds of building stone of which nearly all the great city of Paris is made. How did they do this? The little jelly-like creatures wantedcovering for their frail bodies, and so gathered from the sea-water particles of lime and built them into shells. Millions upon millions of these shells fell down in layers on the sea-floor, and then water, weight, and heat became the forces to consolidate the myriads of shells into stone. The processes of earth-building are slow and long.

The last world-building period, the Neozoic, had five ages. You will find their rather hard names on the plate which is our frontispiece. We might look at them as a splendid panorama. Shall we imagine that as fairies flitting through the woods; gnomes guarding the treasures of the earth; fair Pixies, floating in the rivers and seas; or giant Afrites standing in the hottest sunshine on the desert, we watch these five beautiful and wonderful ages roll on?

What shall we see? Palms first: great tracts of palms, waving their feathery tops against the sky. The earth was warmer in those days than now, and plants and animals, now ranked as tropical, were found as far north as England. Not only were there palms widely spread, but cypress, plane trees, maples, elms, oaks, red-woods, figs, sweet gums, sour gums, tupelos, cinnamon and clove trees. The cape jasmine swung its censers of perfume; ferns and mosses made the woodland depths soft and green. Through these forests, and over the grassy plains, roved hyenas, wolves, bears, elk, antelopes. The famous mastodon was there, with many forms of deer, and thick-skinned creatures of the elephant and rhinoceros tribes that are now known no more. Along the river sides, among the sedges, were great wading birds, turtles, tortoises, crocodiles, serpents. Insects and birds increased,and here and there a monkey might be seen climbing among the tree-tops.

As time moved on, a new, strange change overtook the earth. The climate in the Northern hemisphere became colder and colder; frost and snow held possession of lands that had hitherto been warm and sunny. Colder, still colder; what is called the Glacial or Frozen period was drawing on. As the atmosphere and soil chilled, fir, pine, birch, and dwarf willow succeeded to the palms; animals of woollier coats lived where the thick-skinned, smooth-coated, tropical animals had found a home. The ice-sheet, which at this day wraps the poles, began to extend southward, and an icy sea, such as now washes the shores of Greenland and the North Cape, rolled over the northern half of the globe.

The Ice period has occasioned much dispute and wonderment among men of science. Its remaining traces are chiefly drift, ice-markings such as ice-worn rocks and boulders, with the bones of animals and the traces of Arctic plants found far south of the regions which such organisms occupy at the present time, or did occupy in an age earlier than the Glacial. They indicate a period when ice and cold had sway in lands now temperate.

In a future chapter we shall consider for a little the work of icebergs and glaciers in carving the world. At present we can only say that geologists consider that the ice-cap came down to the 40° parallel of latitude north, while others believe that the frequent ice-markings and boulders found throughout the temperate zone are the work of icebergs drifting in Arctic currents, and swept much furthersouth than they are now seen. Up to this period we have considered red-hot worlds, melted worlds, drowned worlds; the Glacial age gives us a frozen world.

But the one great fact written over the face of the globe is change. Earth-building sweeps through great circles or periods of change. That a certain state exists is, it seems, merely proof that presently it will not be, but will have made room for some new and different state. Even the Ice age was not to last forever. Frost was king for a time, as fire had been king and water had been king. But the Ice age began at last to loosen its cold clasp upon the world. The atmosphere grew warmer; the land rose up above the icy seas; the bergs sailed into equatorial regions and were dissolved in the warm currents of the Gulf Stream.

The Northern hemisphere never returned to the warmth of climate it had enjoyed before the Ice age came on, but it gained the mild temperature of to-day. As the ice-sheet slowly retreated plants sprang up on the earth, the flora following the withdrawing edges of the ice. There was an age when in England and Ireland and France flowers bloomed which now are found only on the high Alps. After a time the flora of the earth became what it is now.

The mastodon and his associates disappeared, and sheep, horses, and dogs, and the bovine animals,—the animals that especially contribute to the comfort and service of man,—became numerous. On the surface of the earth streams and rivers did their work, and arable land was ready for coming harvests. The Ice age had been a bitter winter time; it was followed by a spring. Centuries stormy as March, andchangeful as April, and soft as May, followed each other, bringing the earth-building epochs to a close, and putting on the globe the finishing touches to fit it for the home of humanity. Now at last were seen the cereals, the corn-food of man, the stately and golden maize, the silver wheat, the bearded barley. With these came the gourd and lupine families, bringing us all manner of melons, cucumbers, pumpkins, peas, lentiles, and beans. The hosts of the apple order of fruits were marshalled in array; the peach, plum, cherry, apple, pear. The vine and the olive covered the slopes; earth was now a rich and splendid kingdom waiting for its destined king. The king came, and flora and fauna were at his service; his name wasMan.

FOOTNOTES:[14]Nature Reader, No. 3, p. 23.[15]Nature Reader, No. 2.

[14]Nature Reader, No. 3, p. 23.

[15]Nature Reader, No. 2.

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