Part 3 (2/2)

Several eggs, too--or, rather, casts of eggs--have lately been found in the Cretaceous and Miocene strata of the West; and, as eggs and birds are usually a.s.sociated, we are liable at any time to come upon the bones of the birds that laid them.

To the writer's mind no thoroughly satisfactory explanation has been given for the scarcity of bird remains; but the reason commonly advanced is that, owing to their lightness, dead birds float for a much longer time than other animals, and hence are more exposed to the ravages of the weather and the attacks of carrion-feeding animals. It has also been said that the power of flight enabled birds to escape calamities that caused the death of contemporary animals; but all birds do not fly; and birds do fall victims to storms, cold, and starvation, and even perish of pestilence, like the Cormorants of Bering Island, whose ranks have twice been decimated by disease.

It is true that where carnivorous animals abound, dead birds do disappear quickly; and my friend Dr. Stejneger tells me that, while hundreds of dead sea-fowl are cast on the sh.o.r.es of the Commander Islands, it is a rare thing to find one after daylight, as the bodies are devoured by the Arctic foxes that prowl about the sh.o.r.es at night.

But, again, as in the Miocene of Southern France and in the Pliocene of Oregon, remains of birds are fairly numerous, showing that, under proper conditions, their bones are preserved for future reference, so that we may hope some day to come upon specimens that will enable us to round out the history of bird life in the past.

_REFERENCES_

_The first discovered specimen of Archaeopteryx, Archaeopteryx macrura, is in the British Museum, the second more complete example is in the Royal Museum of Natural History, Berlin. The largest collection of toothed birds, including the types of Hesperornis, Ichthyornis and others, is in the Yale University Museum, at New Haven. The United States National Museum at Was.h.i.+ngton has a fine mounted skeleton of Hesperornis, and the State University of Kansas, at Lawrence, has the example showing the impressions of feathers._

_For scientific descriptions of these birds the reader is referred to Owen's paper ”On the Archaeopteryx of von Meyer, with a Description of the Fossil Remains, etc.,” in the ”Transactions of the Philosophical Society of London for 1863,” page 33, and ”Odontornithes, a Monograph of the Extinct Toothed Birds of North America,” by O. C. Marsh. Much popular and scientific information concerning the early birds is to be found in Newton's ”Dictionary of Birds,” and ”The Story of Bird Life,”

by W. P. Pycraft; the ”Structure and Life of Birds,” by F. W. Headley; ”The Story of the Birds,” by J. Newton Baskett._

[Ill.u.s.tration: Fig. 17.--Archaeopteryx as Restored by Mr. Pycraft.]

VI

THE DINOSAURS

”_Shapes of all sorts and sizes, great and small._”

A few million years ago, geologists and physicists do not agree upon the exact number, although both agree upon the millions, when the Rocky Mountains were not yet born and the now bare and arid western plains a land of lakes, rivers, and luxuriant vegetation, the region was inhabited by a race of strange and mighty reptiles upon whom science has bestowed the appropriate name of Dinosaurs, or terrible lizards.

Our acquaintance with the Dinosaurs is comparatively recent, dating from the early part of the nineteenth century, and in America, at least, the date may be set at 1818, when the first Dinosaur remains were found in the Valley of the Connecticut, although they naturally were not recognized as such, nor had the term been devised. The first Dinosaur to be formally recognized as representing quite a new order of reptiles was the carnivorous Megalosaur, found near Oxford, England, in 1824.

[Ill.u.s.tration: Fig. 18.--Thespesius. A Common Herbivorous Dinosaur of the Cretaceous. _From a drawing by Charles R. Knight._]

For a long time our knowledge of Dinosaurs was very imperfect and literally fragmentary, depending mostly upon scattered teeth, isolated vertebrae, or fragments of bone picked up on the surface or casually encountered in some mine or quarry. Now, however, thanks mainly to the labors of American palaeontologists, thanks also to the rich deposits of fossils in our Western States, we have an extensive knowledge of the Dinosaurs, of their size, structure, habits, and general appearance.

There are to-day no animals living that are closely related to them; none have lived for a long period of time, for the Dinosaurs came to an end in the Cretaceous, and it can only be said that the crocodiles, on the one hand, and the ostriches, on the other, are the nearest existing relatives of these great reptiles.

For, though so different in outward appearance, birds and reptiles are structurally quite closely allied, and the creeping snake and the bird on which it preys are relatives, although any intimate relations.h.i.+p between them is of the serpent's making, and is strongly objected to by the bird.

But if we compare the skeleton of a Dinosaur with that of an ostrich--a young one is preferable--and with those of the earlier birds, we shall find that many of the barriers now existing between reptiles and birds are broken down, and that they have many points in common. In fact, save in the matter of clothes, wherein birds differ from all other animals, the two great groups are not so very far apart.

The Dinosaurs were by no means confined to North America, although the western United States seem to have been their headquarters, but ranged pretty much over the world, for their remains have been found in every continent, even in far-off New Zealand.

In point of time they ranged from the Trias to the Upper Cretaceous, their golden age, marking the culminating point of reptilian life, being in the Jura.s.sic, when huge forms stalked by the sea-sh.o.r.e, browsed amid the swamps, or disported themselves along the reedy margins of lakes and rivers.

They had their day, a day of many thousand years, and then pa.s.sed away, giving place to the superior race of mammals which was just springing into being when the huge Dinosaurs were in the heyday of their existence.

And it does seem as if in the dim and distant past, as in the present, brains were a potent factor in the struggle for supremacy; for, though these reptiles were giants in size, dominating the earth through mere brute force, they were dwarfs in intellect.

The smallest human brain that is thought to be compatible with life itself weighs a little over ten ounces, the smallest that can exist with reasoning powers is two pounds; this in a creature weighing from 120 to 150 pounds.

<script>