The Dinosaurs of Wyoming - Wyoming State Geological Survey ...

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80 THE DINOSAURS OF WYOMING The life conditions and relationships of that most bizarre dinosaUl-ian reptile, Stegosaurus, are thus discussed by Lull: "The genus Stegosaurus is confined exclusively to the Morrison formation, upper Jurassic or lower Cretaceous of Wyoming.... The character of the environment was probably similar to the conception offered by Hatcher, who believed that the Morrison beds were deposited 'over a comparatively low and level plain which was occupied by an interlacing system of river channels. The climate was warm, and the region was overspread by luxuriant forests and broad savannas ... conditions doubtless similar to those now found about the mouth of the Amazon and over some of the more elevated plains of western Brazil.' In spite of the numerous remains of plant-feeding animals, the actual relics of fossil plants are relatively few, nor does the sediment in which these remains are found give other evidence of abundant vegetation. Hatcher's inference of 'luxuriant forests' is, therefore, as yet unproved by direct evidence. "The water areas, as has been shown, were doubtless the d\yelling places of the huge contemporaneous Sauropods, while Stegosaurus was terrestrial and possibly frequented the forests in search of the tender but luxuriant vegetation upon which it browsed. It may well be that the extreme relative narrowness was an adaptation to forest conditions and afforded ease of passage between the trunks of the tree ferns, conifers, and other vegetation of that day. Stegosaurus is rarely found entombed with saumpod dinosaurs, but, on the contrary, is often found isolated or in company with the bipedal unarmored herbivorous Camptosaurus, the nearest equivalent of the European Iguanodon, and with the fleet Dryosaurus; and of carnivores, the agile Coelurus and the blood-thirsty Allosaurus, which was probably its greatest enemy. "I imagine much of the bizarre character of the armor of Stegosaurus was due to the over-specialization accompanying racial old age, but it was nevertheless in many respects admirably adapted to meet on a more or less equal footing the huge well-armed carnivore last mentioned, It would seem as though Stegosaurus, instead of presenting his front to the enemy, turned the rear, possibly crouching low in front as the crocodile does, and, with vigorous sweeps of the terrific tail, impaled the exposed ventral portion of the bipedal carnivore upon the caudal spines and sharp-edged plates. "The long hind limbs imply a rather rapid progression, while the powerful fore limbs were not only for locomotor purposes but fOI- rapidly pivoting the body to prevent either a frontal or flank attack. "Of the evolutionary history of Stegosaurus, we know but little. It seems, however, to have been a migrant fr0111 Europe, having its nearest relatiYe in Omosaurus, remains 'of which are kno\yn as far back as the Dogger of England.
THE ARMOURED DINOSAURIA "In Omosaurus durobrivensis from the Oxfordian of England, which I studied this summer in Cambridge and in the British Museum of Natural History, I find what may readily be a direct ancestor of the American types. The plates and FIGURE 27. Protected by thick plates and massive spines, this great armored dinosaur, the top view of which is shown in the picture, must have been a veritable super·dreadnaught of the animal world. Observe the rows of large plates in the neck region and fore part of the trunk.-After Matthew. spines are present, and, in every respect, the older animal differs only in being of a more generalized character. On the other hand, O. armatus of Owen, from the Kimmeridgian, though nearer Stegosaurus in time, is less like it than is its pre- 81
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'The CVinosaurs of Wyoming By ROY L
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Tragedy of the Mesozoic All the ele
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The DINOSAURS of Wyoming By ROY L.
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LIST OF ILLUsTRA'frONS IX Figure 32
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PREFACE The subject of dinosaurs in
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CHAPTER 1. What Are the Dinosaurs?
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2 CHAPTER II The Geological Age of
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CHAPTER III Their Origin and Distri
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THEIR ORIGIN Ai"D DISTRIBUTIOK 23 A
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CHAPTER IV Historical Account of th
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Page 32 and 33: 92 THE DIKOSAURS OF 'WYOMING of bro
Page 34 and 35: 94 THE DI OSAURS OF WYOMI G small p
Page 38 and 39: 'C '" FIGURE 40.-DISEASE AND INJURY
Page 40: FIGURE 41.-INJURIES AMO"G FOSSIL VE
Page 43 and 44: FIGURE 42.-FRACTURE 'AND NECROSIS I
Page 47: THE THREE-HORNED DINOSAURS 107 horn
Page 50: CHAPTER XIX Animals Which Lived wit
Page 53 and 54: CHAPTER XX Wyoming Dinosaurs Abroad
Page 58 and 59: CHAPTER XXII QLOSSARY Amphibious Di
Page 63: "SACRAL BRAIN" OF DIi\TOSAURS depar
Page 67 and 68: CHAPTER XIV Footprints of Dinosaurs
Page 70: CHAPTER XV The Armoured Dinosauria
Page 73 and 74: THE ARMOURED DIKOSAURIA 73 of penta
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Page 78 and 79: FIGURE 25.-RESTORATION OF THE PALAE
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Page 88 and 89: CHAPTER XVII The Carnivorous Dinosa
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Page 106 and 107: 40 THE DINOSAURS OF WYOMING Wyoming
Page 109 and 110: FIGURE 8. Map of Niobrara County. W
Page 111: DIFFERENT KINDS OF DIKOSACRS 45 "Co
Page 115 and 116: FIGURE IO.-PATHOLOGICAL LESIONS IN
Page 117 and 118: FIGURE
Page 119 and 120: FIGURE 14. The Haemangioma. or vasc
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