Page:Popular Science Monthly Volume 3.djvu/443

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FOOTPRINTS IN THE ROCKS.

429

philosophic induction was the result of his observation, and he immediately remarked to his wife: "There are some turkey's tracks made three thousand years ago!"

These two minds, though untutored in scientific lore, each independently of the other, expressed that fundamental generalization of paleontology which has never been set aside, though wondrously amplified and illustrated since that time: that these impressions were made by living animals in immensely remote periods, when the physical geography of the country differed from what it is at present—that is to say, when the existing solid ledges were in the formative process.

Mr. Draper soon communicated his views to his friends, especially to Captain John Wilson. Captain Wilson did the same to Dexter Marsh, and Mr. Marsh to the village physician, Dr. James Deane. All these gentlemen coincided with the theory of Mr. Draper, that the markings were turkey-tracks; but, as none of them were geologists, they felt the need of competent advice. Accordingly, Dr. Deane sent descriptions of the slabs to the State Geologist, the late Prof. Edward Hitchcock, of Amherst, urging him to come and examine them. A similar sketch was sent to the late Prof. Benjamin Silliman, of New Haven, who expressed no opinion about it, but wished Prof. Hitchcock to investigate the subject. As soon as it was convenient, this gentleman went to Greenfield and examined the specimens. His acquaintance with geological literature and methods of investigation apprised him that this new theory, though plausible, must pass through a severe ordeal before it could be established. Not merely was it questionable whether footprints could be preserved for ages, but it was a monstrous assumption—unheard of in geological circles—to talk of birds as a part of the Triassic fauna! Such an announcement could not fail to evolve unanimous disapproval; and, if premature, if published without careful investigation, it might prove to be an egregious blunder, and haunt the unfortunate author through his lifetime.

The scientific investigation of the subject having been thus urgently placed in Prof. Hitchcock's hands by those immediately and remotely interested, he spent the summer of 1835 in studying the characters derived from the progression of animals, whether birds or quadrupeds. Visits were made to all the sandstone-quarries in the Connecticut Valley, to menageries, museums, and libraries, thus insuring the inspection of all slabs exhibiting similar impressions, an examination of the feet of living animals, especially of those most nearly allied to the new forms, and the assurance that nothing similar had ever been found in any part of the world. The result of this protracted investigation indicated the truth of the first surmises—that these impressions were actually made by the feet of birds in the Triassic period. A full account of the discoveries was published in Prof. Silliman's magazine, the American Journal of Science and Art for January, 1836. Descriptions were given of seven species of avian im-