Part 4 (2/2)
These forms we have been considering were the giants of the group, but a commoner species, Thespesius, though less in bulk than those just mentioned, was still of goodly proportions, for, as he stalked about, the top of his head was twelve feet from the ground.
Thespesius and his kin seem to have been comparatively abundant, for they have a wide distribution, and many specimens, some almost perfect, have been discovered in this country and abroad. No less than twenty-nine Iguanodons, a European relative of Thespesius, were found in one spot in mining for coal at Bernissart, Belgium. Here, during long years of Cretaceous time, a river slowly cut its way through the coal-bearing strata to a depth of 750 feet, a depth almost twice as great as the deepest part of the gorge of Niagara, and then, this being accomplished, began the work of filling up the valley it had excavated.
It was then a sluggish stream with marshy borders, a stream subject to frequent floods, when the water, turbid with mud and laden with sand, overflowed its banks, leaving them, as the waters subsided, covered thickly with mud. Here, amidst the luxuriant vegetation of a semi-tropical climate, lived and died the Iguanodons, and here the pick of the miner rescued them from their long entombment to form part of the treasures of the museum at Brussels.
Like other reptiles, living and extinct, Thespesius was continually renewing his teeth, so that as fast as one tooth was worn out it was replaced by another, a point wherein Thespesius had a decided advantage over ourselves. On the other hand, as there was a reserve supply of something like 400 teeth in the lower jaw alone, what an opportunity for the toothache!
And then we have a mult.i.tude of lesser Dinosaurs, including the active, predatory species with sharp claws and double-edged teeth. Megalosaurus, the first of the Dinosaurs to be really known, was one of these carnivorous species, and from our West comes a near relative, Ceratosaurus, the nose-horned lizard, a queer beast with tiny fore legs, powerful, sharp-clawed hind feet, and well-armed jaws. A most formidable foe he seems, the more that the hollow bones speak of active movements, and Professor Cope pictured him, or a near relative, vigorously engaged in combat with his fellows, or preying upon the huge but helpless herbivores of the marshes, leaping, biting, and tearing his enemy to pieces with tooth and claw.
Professor Osborn, on the other hand, is inclined to consider him as a reptilian hyena, feeding upon carrion, although one can but feel that such an armament is not entirely in the interests of peace.
Last, but by no means least, are the Stegosaurs, or plated lizards, for not only were they beasts of goodly size, but they were among the most singular of all known animals, singular even for Dinosaurs. They had diminutive heads, small fore legs, long tails armed on either side near the tip, with two pairs of large spines, while from these spines to the neck ran series of large, but thin, and sharp-edged plates standing on edge, so that their backs looked like the bottom of a boat provided with a number of little centreboards. Just how these plates were arranged is not decided beyond a peradventure, but while originally figured as having them in a single series down the back it seems much more probable that they formed parallel rows.
[Ill.u.s.tration: Fig. 23.--The Horned Ceratosaurus. A Carnivorous Dinosaur. _From a drawing by J. M. Gleeson._]
The largest of these plates were two feet in height and length, and not more than an inch thick, except at the base, where they were enlarged and roughened to give a firm hold to the thick skin in which they were imbedded. Be it remembered, too, that these plates and spines were doubtless covered with horn, so that they were even longer in life than as we now see them. The tail spines varied in length, according to the species, from eight or nine inches to nearly three feet, and some of them have a diameter of six inches at the base. They were swung by a tail eight to ten feet long, and as a visitor was heard to remark, one wouldn't like to be about such an animal in fly time.
Such were some of the strange and mighty animals that once roamed this continent from the valley of the Connecticut, where they literally left their footprints on the sands of time, to the Rocky Mountains, where the ancient lakes and rivers became cemeteries for the entombment of their bones.
The labor of the collector has gathered their fossil remains from many a Western canyon, the skill of the preparator has removed them from their stony sepulchres and the study of the anatomist has restored them as they were in life.
_REFERENCES._
_Most of our large museums have on exhibition fine specimens of many Dinosaurs, comprising skulls, limbs, and large portions of their skeletons. The American Museum of Natural History, New York, has the largest and finest display. The first actual skeleton of a Dinosaur to be mounted in this country was the splendid Claosaurus at the Yale University Museum, where other striking pieces are also to be seen. The mounting of this Claosaurus, which is 29 feet long and 13 feet high, took an entire year. The United States National Museum is particularly rich in examples of the great, horned Triceratops, while the Carnegie Museum, Pittsburgh, has the best Diplodocus. The Field Columbian Museum and the Universities of Wyoming and Colorado all have good collections._
[Ill.u.s.tration: Fig. 24.--Stegosaurus. An Armored Dinosaur of the Jura.s.sic. _From a drawing by Charles R. Knight._]
_The largest single bone of a Dinosaur is the thigh bone of a Brontosaurus in the Field Columbian Museum, this measuring 6 feet 8 inches in length. The height of a complete hind leg in the American Museum of Natural History is 10 feet, while a single claw measures 6 by 9 inches. The skeleton of Triceratops restored in papier-mache for the Pan-American Exposition measured 25 feet from tip of nose to end of tail and was 10 feet 6 inches to the top of the backbone over the hips, this being the highest point. The head in the United States National Museum used as a model is 5 feet 6 inches long in a straight line and 4 feet 3 inches across the frill. There is a skull in the Yale University Museum even larger than this._
_Articles relating to Dinosaurs are mostly technical in their nature and scattered through various scientific journals. The most accessible probably is ”The Dinosaurs of North America,” by Professor O. C. Marsh, published as part of the sixteenth annual report of the United States Geological Survey. This contains many figures of the skulls, bones, and entire skeletons of many Dinosaurs._
[Ill.u.s.tration: Fig. 25.--Skull of Ceratosaurus. _From a specimen in the United States National Museum._]
VII
READING THE RIDDLES OF THE ROCKS
”_And the first Morning of Creation wrote What the Last Dawn of Reckoning shall read._”
It is quite possible that the reader may wish to know something of the manner in which the specimens described in these pages have been gathered, how we acquire our knowledge of Brontosaurus, Claosaurus, or any of the many other ”sauruses,” and how their restorations have been made.
There was a time, not so very long ago, when fossils were looked upon as mere sports of Nature, and little attention paid to them; later their true nature was recognized, though they were merely gathered haphazard as occasion might offer. But now, and for many years past, the fossil-bearing rocks of many parts of the world have been systematically worked, and from the material thus obtained we have acquired a great deal of information regarding the inhabitants of the ancient world. This is particularly true of our own western country, where a vast amount of collecting has been done, although very much remains to be done in the matter of perfecting this knowledge, and hosts of new animals remain to be discovered. For this information we are almost as much indebted to the collector who has gathered the needed material, and the preparator whose patience and skill have made it available for study, as to the palaeontologist who has interpreted the meaning of the bones.
To collect successfully demands not only a knowledge of the rocks in which fossils occur and of the localities where they are best exposed to view, but an eye quick to detect a piece of bone protruding from a rock or lying amongst the shale, and, above all, the ability to work a deposit to advantage after it has been found. The collector of living animals hies to regions where there is plenty for bird and beast to eat and drink, but the collector of extinct animals cares little for what is on the surface of the earth; his great desire is to see as much as possible of what may lie beneath. So the prospector in search of fossils betakes himself to some region where the ceaseless warfare waged by water against the dry land has seamed the face of the earth with countless gullies and canyons, or carved it into slopes and bluffs in which the edges of the bone-bearing strata are exposed to view, and along these he skirts, ever on the look-out for some projecting bit of bone. The country is an almost shadeless desert, burning hot by day, uncomfortably cool at night. Water is scarce, and when it can be found, often has little to commend it save wetness; but the collector is buoyed up through all this with the hope that he may discover some creature new to science that shall not only be bigger and uglier and stranger than any heretofore found, but shall be the long-sought form needed for the solution of some difficult problem in the history of the past.
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