Читать книгу All About Dinosaurs - Roy Chapman Andrews - Страница 4

Table of Contents

Scientists had been digging up the fossilized remains of other animals for some years before dinosaurs were discovered. The first ever found, or at least recorded, was unearthed at East Windsor, Connecticut, in 1818. No one knew to what creature the bones belonged.

Years later Professor Marsh gave them the name Anchisaurus (An´-key-sawr´-us).

In 1822, the wife of Dr. Gideon Mantell discovered some peculiar teeth in the rocks of Sussex, England. No one at that time had ever heard of a dinosaur. Dr. Mantell sent the teeth to several other scientists. At first they said the teeth belonged to a rhinoceros.

That didn't seem right to Mantell, and he went back to the place where the teeth had been found. There he dug up a number of bones. He studied them for a long time.

Finally he decided they represented a new type of large reptile. He described and named it Iguanodon (Ig-wan´-o-don) because the teeth looked like those of the living iguana lizard.

But it was Sir Richard Owen who recognized that these extinct reptiles needed a general name. He called them dinosaurs, meaning "terrible lizards."

Strangely enough one of the first discoverers of fossil reptiles was not a scientist but a young girl, named Mary Anning. She lived on the coast of southern England. She used to help her father hunt for fossil sea shells. These they sold to tourists who came to the village in the summer.

In 1811, when Mary was twelve years old, she made a great discovery. It was the petrified skeleton of a reptile that lived in the sea when dinosaurs ruled the land. It was quite unknown. The animal was named Ichthyosaurus (Ik´-thee-o-sawr´-us).

Mary's reptile created great excitement among scientists. She searched the rocks near her home and found other petrified marine or sea animals. When her father died, she went into the business of fossil collecting.

In 1821, Mary Anning unearthed the first skeleton of a sea serpent which was named Plesiosaurus (Plees´-i-o-sawr´-us). Seven years later she made another important discovery. It was the skeleton of a pterodactyl (ter-o-dack´-til), a flying reptile. This was the first of its kind ever known from England. Mary Anning made quite a little money selling the fossils to museums all over the world. Her name became famous in science.

Dinosaurs not only left their bones in the rocks; they also left their footprints. The Connecticut Valley has some of the best preserved dinosaur tracks in the world.

In 1802, a farmer named Pliny Moody, ploughed up a block of stone. It showed small imprints like those of a bird's feet. These were called the tracks of Noah's raven. People let it go at that. Others were found, but no one paid much attention to them until 1835.

Then Professor Hitchcock of Amherst College studied them and decided they had been made by large extinct birds. Not until later was it understood that they were the tracks of dinosaurs that walked on their hind legs. Professor Hitchcock's mistake was quite natural. Dinosaurs were almost unknown at that time, and the three-toed footprints look very much like those of birds.

The Connecticut dinosaur tracks are very, very old. They were made about 200 million years ago at the beginning of the Age of Reptiles.

The face of Connecticut has changed much since those dim dark days. It was not beautiful then as it is now. The landscape was all dull green. There was little vegetation except conifers, ferns, and cycads (cy´-kads) which are trees something like palms and ferns. Not a single flower gave color to the forests. There were no brilliant tints of autumn leaves in October. Neither were there birds. Turtles swam in the ponds, lizards slept in the sun, and small dinosaurs skipped about in unbelievable millions.

The story of the Connecticut tracks is an important chapter in the history of dinosaurs. That part of the Connecticut River Valley, where the footprints are found, was an ancient river bed. Or it may have been a long shallow arm of the sea. Its water level changed greatly. Large stretches would be left dry to bake in the sun for days or weeks. Then suddenly they would be covered with muddy water.

For some reason, dinosaurs liked to come to this river flat. When they walked across it, their feet sank into the soft mud and left deep imprints. Then the mud dried up and baked in the sun. When the flats were again covered with water, sediment filled the tracks and made casts. After many years the mud became hard rock.

Thousands of tracks have been preserved in this way. Dinosaurs must have been there in millions. Their footprints show they were of many different kinds and sizes. The largest tracks are fifteen inches long and three feet apart. They were made by really big dinosaurs which walked on their hind feet. Probably the animals had small front limbs like those of a kangaroo. This seems to be true, because there are impressions of dinosaur "hind ends" where they sat down to rest. With these are casts of the smaller forelegs in just the right position where they touched the ground.

It is strange that very few bones of these reptiles have been found. Probably the rocks containing their skeletons lie out to sea. The bodies must have been carried away by tides or currents before they had time to be buried and fossilized on land.

Connecticut is by no means the only place where dinosaur footprints have been found. Texas, Montana and other states can boast of bigger and better tracks but not so many as in Connecticut. About 1830, in England, dinosaur footprints were discovered in rocks of the same age as those in Connecticut. But no bones of the reptiles that made them have been discovered. For some reason these tracks all go from west to east. Perhaps the dinosaurs were migrating or traveling a regular road to their feeding grounds. Belgium, too, has some very fine tracks of the big Iguanodon, the same type of dinosaur that Dr. Mantell described.

At first, most fossils were found only by accident. When digging the foundations of a house, making a road, or getting slate out of a quarry, men would turn up strange bones. They would take them home, and their families would keep them as curiosities for a while. Eventually some of the bones would be presented to a museum where they were studied by scientists.

Year by year, interest grew in the past life of the earth. It was slow because most people think only about what happens this year or what will happen next year. That seems more important than anything that happened fifty, or a hundred or a thousand years ago. But some of them knew that you can't understand the present, unless you learn what went on in the past. Scientists realized that fossil bones and plants are pages from the history of the earth. They were written in stone instead of words on paper, but they could tell a true story just the same.

So more and more scientific men began studying fossils. They found it very exciting. It was like a detective novel. They had to piece together the strange, unreal life of the world millions of years ago. They did it from the impressions of plants left in the rocks, from fossil bones, and from insects, and bits of petrified wood.

A detective does the same thing when he starts to solve the mystery of a robbery or a murder. He finds a handkerchief, a bit of ribbon or a shred of clothing. Those are his clews. He puts them all together, and they begin to form a pattern in his mind. With a little imagination he thinks he knows what happened. So he takes his evidence into court.

That is the way a scientist works when he tries to reconstruct the prehistoric world. He studies the bones and the plants and the fossilized wood. He decides what the climate was like and the vegetation and the sort of animals that lived there. He presents his case to other scientists. Perhaps his evidence isn't good enough for them to agree he is right. So he just waits. He hopes that after a while more evidence will be discovered in the rocks to prove his case.

I know how exciting it is because I am one of the detectives who have been collecting the fossil evidence. Never in my life have I done anything more fascinating. You can do it, too, if you will only keep your eyes open when you prowl around rocks. Perhaps you may find a dinosaur bone or some other fossil. Mary Anning did it when she discovered some of the first sea serpents. She made herself famous.

Until after the Civil War, people in America were busy trying to preserve the union of the states. They didn't think much about anything else. But when peace came, their attention turned to our great western country. The U.S. Government sent out exploring parties. Usually they had geologists with them, for they wanted to find out about minerals and other things in the earth. These men discovered hundreds of fossil bones and many dinosaurs. Thus began the organized work of collecting fossils in America.

The study of fossils is called paleontology (pay-lee-on-tol´-o-gy). The word means "the science of ancient living beings." Two American paleontologists were very important at that time. One was Professor Edward D. Cope of Philadelphia. The other was Professor O. C. Marsh of Yale University. Both were rich men. Between the years 1870 and 1895, they sent out their own collecting parties. Those went to the Great Plains and the Rocky Mountain basins. They found that the badlands of Wyoming and Montana were filled with fossils. Many dinosaur skeletons were discovered.

But it was dangerous work in those early years. Indians were still on the warpath in places. A collector might be walking along the side of a ravine with his eyes on the ground. An Indian could easily sneak up and send an arrow or a rifle bullet into his body. Still the work went on.

At first Cope and Marsh were friends. Later they became rivals and bitter enemies. It was a race with them to see who could get the most fossil animals and name them. We know now that it was a foolish race. There are enough fossils for everybody in that vast country.

But it had many good results. One of them was to get scientists in other countries more keenly interested and start them to work. Also, museums began to send expeditions for fossil collecting all over the world. That is how I happened to go to Asia, to the Gobi Desert of Mongolia. I went for the American Museum of Natural History in New York. There I did my first fossil hunting and found my first dinosaur.