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58 MEMOIRS OF THE CARNEGIE MUSEUM 
ponderous reptiles were actually aquatic they would require bodies of water of no 
inconsiderable dimensions and depth for their accommodation and it is not at all 
reasonable to suppose that when overtaken by death either through disease, old 
age or the attacks of their enemies they would seek other than their natural habitat. 
Therefore if they lived and died in deep water, after death it is only natural to 
suppose that their carcasses would sink to the bottom and become buried beneath 
the accumulating sands and clays with the different bones of the skeleton still in 
their proper positions relative to one another. For among the strictly aquatic 
forms (crocodiles, etc.) that lived contemporaneously with them there are none 
sufficiently large and powerful to disarticulate the skeletons of these gigantic 
dinosaurs. Since in most instances the skeletons of these dinosaurs are found in 
even more disarranged and dismembered conditions than were the two described in 
the present paper it seems far more probable that, as a rule, they have met death in 
or adjacent to shallow waters, or on land where their carcasses were accessible to 
the terrestrial carnivorous Dinosauria, to the ravages of which the dismemberment 
of the skeletons is partially due, as is sometimes evidenced by the tooth marks still 
preserved on the bones: silent but unmistakable evidences of those prehistoric 
feasts. 
Fourth: The character of the enclosing matrix furnishes important evidence as to 
the nature of the habitats of those animals whose remains it contains, especially if 
considered in connection with the character of the surrounding and overlying sedi- 
mentary rocks. If as is the case at the quarries near Canyon City, Colorado, the 
bones are found imbedded in lenticular masses of coarse sandstone showing cross- 
bedding it is evident that such deposits were laid down in comparatively shallow 
waters. Furthermore, if as is the case throughout the Jurassic generally, wherever 
important deposits of dinosaur remains have been found, massive, coarse, or finely 
bedded sandstones with or without frequent examples of cross-bedding are found 
replacing the finer, more evenly bedded clays and shales both vertically and later- 
ally even at moderately frequent intervals, it is evident that such beds were not 
deposited in deep and quite waters; that the immediate region, which by every 
reasonable presumption should be considered the habitat of the dinosaurs, presented 
the appearance not of a great sea or lake, but rather of a flat and open country 
where streams were constantly shifting their courses and the smaller lakes and 
bayous, though confined within more fixed limits than the streams were not entirely 
stable. That the country was flat and open rather than mountainous is shown by 
the absence for the most part, of coarse conglomerates. 
