Читать книгу Wealth of the World's Waste Places and Oceania - Jewett C. Gilson - Страница 18

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Although reptiles appeared first in the period known as the Carboniferous Age, or age of plant life, they did not attain their greatest development until Jurassic and Cretaceous times, when many were of prodigious size and ruled the world. The gigantic ichthyosaurs, mesosaurs, and dinosaurs held dominion over the sea and land, and the monster flying reptile, the pterodactyl, over the air.

Ages ago a great inland sea embracing Wyoming and the surrounding region occupied the area east of the Rocky Mountains. For many years students of geology had found this section a fertile field for the study of rock formations and the collection of fossils; but not until 1898 was the geological wonderland of central-south Wyoming discovered.

This discovery proved to be a graveyard of prehistoric monsters dating back probably several millions of years ago. Entombed in the rocks of the Jurassic and Cretaceous periods, many lizard-like animals of gigantic size called saurians were found. Several fossil skeletons of these animals have been chiselled out of the solid rocks and mounted in museums, the work entailing a vast amount of labor and expense. The discovery was made by Mr. Walter Granger, who had been sent out by the American Museum of Natural History, of New York, to hunt for fossils.

In the desert section near Medicine Bow River, Wyoming, he found what seemed to be a number of dark-brown bowlders. On a critical examination they proved to be ponderous fossils that had been washed out of a great bed of reptilian remains. The fossil graveyard in question was found to be two hundred and seventy-five feet in thickness. Near by was a Mexican sheep-herder's cabin, the foundations of which were constructed of huge fossils. The vicinity was christened Bone Cabin Quarry. Ten miles south of the Bone Cabin Quarry, in the Como Bluffs, another bed containing the remains of huge dinosaurs was discovered. From these remarkable cemeteries many fossils have been obtained.

The term saurian means "lizard," and it has many prefixes to indicate the different genera and species. The prefixes generally express to a certain extent the characteristic appearance or habits of the different kinds of saurians. Some were flesh-eaters; others were herbivorous. Some lived on land; others, in the shallow waters and lagoons, fed on succulent aquatic plants; still others frequented the deeper waters and lived on fish.

_Property of the American Museum of Natural History_ The Brontosaurus (herbivorous dinosaur) LINK TO IMAGE

The name dinosaur, meaning terrible lizard, represents an order of fossil reptiles. They are allied to the crocodile, but, like the kangaroo, their hind legs were much longer than their front ones. The neck and tail were very long and the body short but of immense size. These monsters were from twenty to eighty feet in length and weighed from thirty to one hundred tons. The long, slender neck supported a small head that contained a correspondingly small brain, from which it is thought that the creature possessed a low order of intelligence. The tail was much thicker than the neck and in some species was flattened. When rising on its hind legs and resting on its tail it could look into the window of a four-story building. Some of these strange animals had bills like those of a duck; some possessed teeth for grinding and others sharp teeth for tearing. These were by far the largest land animals that ever lived. The different species often waged titanic battles with one another for the supremacy of the earth.

It is conjectured that their disappearance was due to violent upheavals of the earth, to the draining of the water, to changes of climate, and to deprivation of suitable food.

The mounted brontosaur in the American Museum of Natural History, New York, will enable one better to appreciate the size of these giants of the ancient world. This typical specimen, though not the largest found, is sixty-seven feet long and stands fifteen and one-half feet high. Its neck measures thirty feet in length and its tail eighteen. The body weighed about ninety tons. This huge fossil, enclosed in its stone matrix, was sent from the quarry to the museum. After it had been received two men were employed constantly for nearly two and one-half years in removing the matrix, repairing, and mounting the fossil.

Let us turn now to the burying ground of a giant forest. Long, long years ago, before man appeared on the earth, an inland sea occupied what is now the northeastern part of Arizona. It was a sea bordered with sandstone and surrounded by coniferous forests, where stately trees nodded in the breezes.

At length there came a great change. The rim of the basin gave way, and the great volume of water, freed from restraint, overwhelmed the forest with earthy material, prostrating and burying it deep beneath the flood of sand.

In time the woody structure disappeared, and was replaced by beautifully stained opal and agate. Again, in the lapse of time the old forest bed was once more lifted above its former level, forming a mesa, or plateau, of considerable extent. During subsequent ages, the elements scarred and furrowed the plateau, forming canyons, gulches, valleys, and buttes, thus revealing in part this ancient forest. Could these dead trees but talk, how interesting would be their story! We can read their history but imperfectly by examining the mutilated breast of Mother Earth, in and on which lie these mute stone trees, dead yet made more beautiful through their transformation.

_Property of the American Museum of Natural History_ The Allosaurus (carnivorous dinosaur) LINK TO IMAGE

This region is called the "Petrified Forest," or "Chalcedony Park." It is about one hundred square miles in extent, and is visited annually by thousands of people from all parts of the world. On account of its strange geological character it is of special interest to the scientist.

Let us make a brief trip to this wonderful stone forest. We take light hand-baggage and board a Santa Fé train. The railway passes near the most interesting part of the forest, and we change cars before entering Arizona in order to take this line. The railway officials have made a station at Adamana, six miles from the edge of the forest, in order to accommodate the travelling public. We leave the train here and procure a team to carry us to the forest.

Unless informed of what is to be seen one is apt to be greatly disappointed. One's idea of a forest is usually that of a timber-covered area in which the trees stand erect, with outspreading branches; but we look in vain for a standing tree, or even a stump that is erect.

All are branchless trunks, prostrate on the ground, many wholly or partly buried; moreover, they are lying in all sorts of positions, some entire and others broken into sections; some are massed closely together; others lie apart; and millions of pieces of all sizes are scattered around. At places we can travel a long distance by stepping from one log to another.

But what is that pile of variegated disk-like objects looking like the primitive Mexican ox-cart wheels? They are cross-sections of stone logs, some large and some small, seemingly thrown together carelessly. It is a characteristic of petrified trunks to break into cross-sections or blocks, varying from a few inches to several feet in length; and this tendency prevails here.

We are told that the trees of this forest antedate those of the Yellowstone Park by a long period of time. How the loftiest flights of the imagination are piqued as we contemplate the marvellous changes since this primeval forest depended on the soil and sun for their life-giving elements! As we wander through this wonderful forest our feet seem to be treading on the rarest gems. And well may it seem so, because when polished these pieces display a beauty of coloring and a lustre that rivals the glint of precious stones. There is no other petrified forest in the world in which the mineralized wood assumes so many varied and interesting forms and colors.

Many years ago a firm at Sioux Falls undertook to manufacture table tops, mantels, pedestals, and various decorative articles out of sections of this agatized wood by cutting them into the desired forms and polishing them. Tiffany and Company, the famous jewellers, also used this material for the base of the beautiful silver testimonial presented to the French sculptor, Bartholdi.

At a later date, an abrasive company of Denver conceived the plan of grinding up these trunks to make emery because of their extreme hardness; in fact, a plant was shipped to Adamana station for that purpose. Fortunately for the public, however, it was not put into operation because the company learned that a Canadian firm had put on the market an article at such a reduced price that to grind up these beautiful logs would be unprofitable.

Fragments, branches, and trunks of all sorts and sizes are found lying around, many of them richly colored, forming chalcedony, opal, and agate; some approach the condition of jasper and onyx.

Before the Petrified Forest was set aside as a national park by Congress, many acts of vandalism were committed, to say nothing about the quantities of mineral carried away by manufacturing firms and curiosity-hunters. Keepers now have charge of the park, and no one is permitted to take away specimens for commercial use. Previously many of the finest logs were destroyed by blasting in order to procure the beautiful crystals which are found in the centre of many of them.

One object of special interest in the park is the National Bridge, a petrified trunk which spans a chasm thirty feet wide and twenty feet deep. The part of the trunk crossing the gulch lies diagonally and is forty-four feet long. The length of the trunk exposed by erosion is one hundred and eleven feet; a fraction still remains embedded in the sandstone.

The ruins of several ancient Indian pueblos are scattered about the park, nearly all of them built of logs of this richly colored, agatized wood. The forest was a storehouse for ages, whence primitive men obtained material from which to make agate hammers, arrow-heads, and knives, as is shown by implements found hundreds of miles distant from these quarries.