File:The American journal of science (1899) (18153832995).jpg

Title: The American journal of science
Identifier: americanjournal471899newh (find matches)
Year: 1880 (1880s)
Authors:
Subjects: Science
Publisher: New Haven : J. D. & E. S. Dana
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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0. C. Marsh—Footprints of Jurassic Dinosaurs. 231 The interpretation of the various footprints here shown is fortunately a much less difficult matter than that of the huge tridactyle tracks from the Triassic, as in the latter case there was little except conjecture to assist in the investigation. In the present instance, however, it is known that abundant osse- ous remains of large Dinosaurs are imbedded in deposits of the same age, and in the same general vicinity. Some of these reptiles are known to have been bipedal, and quite large enough to make the footprints now discovered. Moreover, the structure of the feet of some of these animals is sufficiently well known to demonstrate clearly that in walking they must have made footsteps similar to, if not identical with, the fossil specimens here recorded. i.
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Figure 1.—Outlines of Jurassic footprints found with those shown on Plate V« a, footprint of large herbivorous reptile ; &, footprint of large carnivorous reptile; c, footprint of smaller carnivorous reptile. All the figures are one-tenth natural size. As to the particular reptiles that made the present foot- prints, we have a hint in the impressions themselves. Some of these show marks of short and wide toes, suggesting that they were made by the robust feet of herbivorous Dinosaurs. The other footprints show impressions of longer and more slender toes, such as are known in the carnivorous Dinosaurs, which lived at the same time and in the same region as the herbivorous forms, and, indeed, preyed upon them. In Plate V, the large figure on the left evidently represents the foot- print of a herbivorous Dinosaur, while the small one on the right, with slender toes, was probably made by a carnivorous form. Of the outline figures above, the one with the thick digital imprints (a) was doubtless made by a herbivorous rep- tile, while the other two (b and c) appear carnivorous in type. In selecting from this horizon the known Dinosaurs that might have made the present footprints, it would be safe to say that the genus Camptosaurus, especially some of its larger species, may be held responsible for the herbivorous footsteps, while its carnivorous enemy, Allosaurus, had representatives to which the more slender impressions may naturally be due.

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