Oldalképek
PDF
ePub

the pachydermata, his predecessors, and those later mammalia, the Cetacea, or whales. There is little doubt that he was an inhabitant of the lakes and marshes, and that he could anchor himself to the firm land by his huge tusks. His singular appearance has inspired some one to write the following:

4.

SONG OF THE DINOTHERIUM.

"My thirst I slake in the cooling lake,
Where I swim among the fishes,

And should hunger gnaw my vacant maw,
A dinner meets my wishes:

For bulbous roots or tender shoots

I dig or crop at pleasure,

And having dined, if to sleep inclined,

I lay me down at leisure.

As a ship will ride in the rushing tide
If her anchors meet the sand,

So when I sleep in the river deep,
My tusks are in the land."

5. In the lower division of the Tertiary the bee first makes its appearance, the fossil remains of one having been found sealed up in a piece of amber-"an embalmed corpse in a crystal coffin," as Hugh Miller beautifully describes it. Coexistent with the bee are the first of the Ophidians or serpents, as shown in a monster species allied to the modern python. Here also we first detect plants and trees belonging to wellknown existing genera and orders, but not of existing species.

6. In the uppermost strata of this period are found remains of the mastodon, and also of numerous species of mammalia almost or nearly identical with many of the existing species. Thus, in vast caves of the later Tertiary period, accidentally opened in many places in Europe and Asia, have been found the skeletons of immense numbers of hyænas, mixed with the bones of the cave-tiger, the cave-bear, the mammoth, and the rhinoceros. The first traces also of ruminant animals appear at this time-of wild oxen, deer, camels, horses, and other creatures of the same class, and, even in high northern lati tudes, the remains of species of elephants now unknown.

Yes! where the huntsman winds his matin horn,
And the couch'd hare beneath the covert trembles;
Where shepherds tend their flocks, and grows the corn;

Where Fashion on our gay parade assembles,

Wild horses, deer, and elephants have strayed,

Treading beneath their feet old Ocean's races.--HORACE SMITH.

LESSON VIII.-THE MODERN GEOLOGICAL PERIOD.

1. THE modern geological period embraces the two eras known as the Drift and the Alluvium. The Drift strata rest upon the Tertiary, and are spread over almost every part of the northern regions of the globe in the form of coarse sand and gravel, beds of clay, and rocks, called boulders, torn from the masses to which they belonged by the force of floods and glaciers; while the Alluvium consists of the surface soil, and layers of loam, sand, and fine gravel, evidently deposited by rivers, or in still water. In the Drift period, which was one of floods of vast extent, the climate of northern countries was evidently colder than during the Tertiary, and probably colder than at present. Hugh Miller describes our earth in this period as "a foundering land under a severe sky, beaten by tempests and lashed by tides, with glaciers half choking up its cheerless valleys, and with countless icebergs brushing its coasts and grating over its shallows."

2. Drift, embracing a period of repeated depressions and elevations of the land, is almost destitute of organic remains of animals and plants that lived during the time of its production; but it abounds in immense quantities of the bones of those large mammalia which must have existed at the close of the Tertiary period. These remains belong principally to animals related to the elephant, as the mammoth and mastodon, and the various species of hippopotamus, rhinoceros, horse, ox, deer, and the animals whose remains were found in the caves already mentioned, and also throughout the frozen regions of northern Asia. The mastodon and a few other monster mammalia, now extinct, appear to have lived as late as the time of the earliest of the alluvial deposits. It is in the Alluvial period only that the remains of MAN and his works have thus far been found. "Geology, scarce less certainly than Revelation itself, testifies that the last-born of creation was man, and that his appearance on earth is one of the most recent events of which it submits the memorials to its votaries." "From harmony-from heavenly harmony

This universal frame began;

From harmony to harmony,

Through all the compass of the notes it ran,
The diapa'son closing full in man.”

3. We have thus hastily glanced at the succession of ages which make up the geological history of our planet. We have seen land and water succeeding each other on our globe in

continual mutations; and we are thence prepared to admit the possibility that

"New worlds are still emerging from the deep,

The old descending in their turn to rise."

But what strikes us with the greatest force is the evidence of the successive creations which have peopled our planet; we have seen race after race of beings starting into exist ence, and then disappearing; for we know, by testimony. which can not be controverted,.that

"The earth has gathered to her breast again,

And yet again, the millions that were born
Of her unnumbered, unremembered tribes,"

and each tribe and race has been adapted to the circumstances in which it was placed, thereby affording the most evident proofs of the wisdom and overruling providence of the Creator. Reflecting on these phenomena, the mind recalls the impressive exclamation of the poet :

"My heart is awed within me when I think
Of the great miracle which still goes on
In silence round me-the perpetual work
Of THY creation, finished, yet renewed
Forever."

LESSON IX.-RETROSPECTIVE VIEW OF GEOLOGY.

LET us now reverse the order of viewing the geological history of our globe, starting from the present, and proceeding backward against the order of time. As the traveler who ascends to the regions of eternal snow gradually loses sight of the abodes of man, and of the groves and forests, till he arrives at sterile plains, where a few stinted shrubs alone meet his eye, and as he advances even these are lost, and mosses and lichens remain the only vestiges of organic life, and these too at length pass away, and he enters the confines of the inorganic kingdom of nature-in like manner the geologist who penetrates the secret recesses of the globe perceives at every step of his progress the existing forms of animals and vegetables gradually disappear, while the shades of other creations teem around him. These, in their turn, vanish from his sight; other new and strange modifications of organic structure supply their place; these also fade away; traces of animal and vegetable life become less and less manifest, till they altogether disappear; and he descends to the primary rocks, where all evidence of organization is lost, and the granite, like a pall thrown over the relics of a former world, conceals forever the earliest scenes of the earth's physical drama. MANTELL.

LES. X.-A VISIT TO THE COUNTRY OF THE IGUANODON. 1. A VIVID idea of the "Age of Reptiles," and also of the subsequent changes in the earth's geological history, is given by the geologist, Dr. Mantell, in the following fanciful sketch, which the reader may suppose to have been written by a higher intelligence, who first visited our sphere "some millions of years ago," in that portion of the Secondary period denominated the "Age of Reptiles," when the now fossil forests of Portland were flourishing. The Sussex coast of England illustrates all the geological changes here described.

2. "Countless ages ere man was created I visited these regions of the earth, and beheld a beautiful country of vast extent, diversified by hill and dale, with its rivulets, streams, and mighty rivers flowing through fertile plains. Groves of palms and ferns, and forests of coniferous trees, clothed its surface; and I saw monsters of the reptile tribe, so huge that nothing among the existing races can compare with them, basking on the banks of its rivers and roaming through its forests; while in its fens and marshes were sporting thousands of crocodiles and turtles. Winged reptiles of strange forms shared with birds the dominion of the air, and the waters teemed with fishes, shells, and Crustacea.

3. "And after the lapse of many ages I again visited the earth; and the country, with its innumerable dragon-forms, and its tropical forests, all had disappeared, and an ocean had usurped their place. And its waters teemed with the nautilus and other molluscs, of races now extinct, and innumerable fishes and marine reptiles.*

4. "And thousands of years rolled by, and I returned, and lo! the ocean was gone, and dry land had again appeared, and it was covered with groves and forests; but these were wholly different in character from those of the vanished country of the iguanodon. And I beheld, quietly browsing, herds of deer of enormous size, and groups of elephants, mastodons, and other herbivorous animals of colossal magnitude. And I saw in its rivers and marshes the hippopotamus, tapir, and rhinoceros; and I heard the roar of the lion and the tiger, and the yell of the hyena and the bear.t

* This represents the chalk formation, embracing the uppermost strata of the Cretaceous system-the highest in the Secondary period. The chalk strata were evidently deposited in an ocean that must have covered, for many ages, the greater part of what is now central and southern Europe.

† This represents the uppermost formations of the Tertiary period the pliocene.

5. "And another epoch passed away, and I came again to the scene of my former contemplations, and all the mighty forms which I had left had disappeared; the face of the country no longer presented the same aspect; it was broken into islands, and the bottom of the sea had become dry land, and what before was dry land had sunk beneath the waves. Herds of deer were still to be seen on the plains, with swine, and horses, and oxen; and wolves in the woods and forests. And I beheld human beings clad in the skins of animals, and armed with clubs and spears; and they had formed themselves habitations in caves, constructed huts for shelter, inclosed pastures for cattle, and were endeavoring to cultivate the soil.*

6. "And a thousand years elapsed, and I revisited the country, and a village had been built upon the sea-shore, and its inhabitants supported themselves by fishing; and they had erected a temple on the neighboring hill, and dedicated it to their patron saint. And the adjacent country was studded with towns and villages; and the downs were covered with flocks, and the valleys with herds, and the corn-fields and pastures were in a high state of cultivation, denoting an industrious and peaceful community.t

7. "And, lastly, after an interval of many centuries, I arrived once more, and the village was swept away, and its site covered by the waves; but in the valley and on the hills above the cliffs a beautiful city appeared, with its palaces, its temples, and its thousand edifices, and its streets teeming with a busy population in the highest state of civilization; the resort of the nobles of the land, the residence of the monarch of a mighty empire. And I perceived many of its intelligent inhabitants gathering together the vestiges of the beings which had lived and died, and whose very forms were now obliterated from the face of the earth, and endeavoring, by these natural memorials, to trace the succession of those events of which I had been the witness, and which had preceded the history of their race."

* This represents the earlier periods of the Alluvium-what Hugh Miller calls the "stone age," in which are found, in the British Isles, remains of man, with weapons and utensils of stone.

+ This represents a period subsequent to the Roman invasion, when the inhabitants of Britain had utensils and weapons formed of iron. Before the Conquest the fishing town of Brighton was on a terrace of beach and sand (which the ocean had abandoned) on the Sussex coast; and the church of St. Nicholas stood inland on a neighboring cliff, which showed the mark of the waves at its base.

This represents the present era. The old fishing-town of Brighton is now covered by the sea, which has resumed its ancient position at the base of the cliffs; and a great city (London) has grown up a little farther inland—the metropolis of a mighty empire.

« ElőzőTovább »