none of the Old World. It was the Megalosaurus of Amer

ica.

Another of the gigantic reptiles which carried on a war of extermination upon the fields destined to be ensanguined by the battles of Trenton and Brandywine was the Hadrosaur (Hadrosaurus Foulki, Leidy). The visitor to the museum of the Academy of Sciences of Philadelphia can not fail to be impressed by the skeleton of one of these monsters mounted in the attitude of browsing from a cycadeous tree. This piece of work is by the eminent restorer of extinct animals, B. Waterhouse Hawkins, Esq., of London, to whose courtesy I am indebted for the photographic view which adorns the opposite page (Fig. 76). The Hadrosaur attained the length of thirty feet. The femur or thighbone was sometimes five feet in length, exceeding by more than a foot the maximum length of the femur of the Iguanodon of England, the largest of the hitherto known land reptiles. The fore limbs were less than half the length of the hind limbs. The form of the feet and toes shows that they were poorly adapted for swimming. In its habitual attitude it rested, like the kangaroo, upon its enormous hind limbs and tail. With its supple anterior extremities it reached upward to the foliage of the tree destined to afford it food, and drew the branches down within the reach of the grinding jaws. Not unlikely this land-monster walked at times upon its hind feet, while the ponderous tail dragged behind.

Fig. 75. Tooth of an ancient New Jersey Saurian (Lælaps aquilunguis), showing two

successors beneath.

Thus, on both continents, gigantic reptiles long time swayed the sceptre over the entire animal creation. But their empire was approaching its end. One of those throes of Nature, through which new annexations of land to the continent were ef fected, ushered in

the closing stage. of Mesozoic Time. The conditions of life were changed; all the peculiar types whose history we have traced dropped out of existence, and mam

mals assumed the

reins of empire. Turtles received accessions of numbers, and serpents now first uncoiled their sinuous lengths, while ba

trachians made the

bayous and marshes resonant with

Fig. 76. The Hadrosaurus.

the varied piping of a myriad voices. Among the latter a salamander, known as Andrias Scheuchzeri, has attracted most attention, in consequence of having for a long time been regarded as the skeleton of a man, who thus, by the fossilization of his remains, was supposed to attest the reality of the Deluge of Noah.

Such is a hasty glance at the Age of Reptiles. Success

I

ive phases of animal life have swept like waves over the surface of our planet, but none has been more striking or more real than that which was dominant through Mesozoic time. Throughout the whole extent of Great Britain there has not been known a single large reptile during the human era; yet in the single era of the Wealden the British dominions maintained four or five species of Dinosaurs fifteen to twenty feet in length, ten or twelve Crocodilians, Lacer tians, and Enaliosaurs ten to fifty or sixty feet in length, besides Pterosaurs and Turtles, to say nothing of the prob ably numerous species whose fossil remains have as yet escaped observation. These successive swells in the stream of animal life are convenient stand-points from which to note the progressive development of organic existence. The history of reptiles, like that of fishes, presents some remarkable exceptional features, which have a most im. portant bearing upon the question of "development," which is taking a front rank among the questions of the age. But these aspects of the case are reserved for future consideration.

CHAPTER XVII.

THE GEOGRAPHY OF THE EMPIRE OF REPTILES.

CONT

ONTINENTS have been developed, like organisms, from their primeval germs. Geologic force, like vital force, operates always toward the accomplishment of some definite end; and, notwithstanding its vicissitudes, there is little difficulty in perceiving how every phenomenon of one age has been contemplated and ministered to by the events of all preceding ages. The American Continent is not a single upthrow of volcanic force, but a gradual growth, beginning before the creation of the first animals and plants, and proceeding by a certain method through all the subsequent ages even to the present, and receiving from time to time such progressively improved existences as its physical circumstances permitted. At first it was an angulated ridge of land in the centre of the present continental area (Fig. 20). Then, by successive upheavals, belts of increment were added on the southeast and southwest, till the ancient ocean has been narrowed to its present limits. Like the exogenous growth of an oak, the increase has been always upon the outside. So the vast continent has been built up and configurated in accordance with a method as definite as that which has shaped the globe itself.

The empire of molluscs saw the greater portion of the continent the bed of the sea. The reign of fishes witnessed the emergence of only the extreme northeastern and northwestern portions of the United States (Fig. 55). In the earlier part of the reign of reptiles New England was a peninsula hemmed in by the broad estuary of the St. Law

rence on the north, and a similar estuary of the embryo Connecticut on the west (Fig. 68). Toward the close of this reign the continent had assumed the similitude of its present form and extent (Fig. 77). The Atlantic coast stretched from the neighborhood of New York City to the Delaware River, and thence southwestward to South Carolina, along a line now sixty or seventy miles inland. Delaware and Chesapeake Bays were consequently out at sea, and the Delaware River emptied into the Atlantic at Trenton. From South Carolina the shore-line turned gradually westward, and crossed the States of Georgia, Alabama, and Mississippi at the distance of one or two hundred miles from the present gulf coast. A deep bay set northward along the future valley of the Mississippi River as far ast the mouth of the Ohio, or beyond, so that at this time the confluence of those two rivers was at their mouth. West of the Missouri was a vast inland sea or elongated gulf, which stretched along the eastern flanks of the Rocky Mountains to the Arctic Ocean. This gulf was perhaps interrupted at one or two places by spurs of the mountains. Into this gulf emptied the Athabasca, Slave, and Great Bear Lakes. The upper watershed of the present Missouri was beneath the sea; and the basin of the Mississippi was more limited in extent than that of the Ohio, which probably was the larger stream. West of this Mediterranean Gulf was a broad belt of land stretching from the isthmus far to the northwest, and probably to Behring's Straits, if not across them. The Pacific coast was a hundred and fifty miles farther inland than at present. Lake Superior was the only one of the great lakes then in existence. The stream which drained it wound past the future sites of Detroit, Cleveland, and Buffalo, and, plunging over the escarpment near Lewiston, became the ancestor of the present St. Lawrence. The basins of the other lakes are the result of