Page:Popular Science Monthly Volume 3.djvu/442

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THE POPULAR SCIENCE MONTHLY.

not to be adequately shown by this brief statement. For, besides generating habits of thought appropriate to the study of the Social Science, it furnishes the mind with special conceptions which serve as keys to the Social Science. The Science of Life yields to the Science of Society certain great generalizations without which there can be no Science of Society at all. Let us go on to observe the relations of the two.

 

FOOTPRINTS IN THE ROCKS.
By CHARLES H. HITCHCOCK, A. M.,

PROFESSOR OF GEOLOGY IN DARTMOUTH COLLEGE.

SEVENTY years ago, a student belonging to Williams College, while holding the plough in his father's field at South Hadley, Massachusetts, turned over a flat slab of sandstone about three feet long. His attention was directed to what seemed to be a row of bird-tracks upon its surface. He had often noticed—as has every intelligent person—the impressions made by the feet of animals in the mud, upon the shores of rivers, lakes, and in the highway. But he had never before seen the imprint of an animal's foot upon the solid rock, and had been taught to believe that the ledges were suddenly called into being by the Almighty without passing through a tedious formative process. Here, however, was a phenomenon not to be explained in accordance with the popular opinion—real footprints in the solid rock—and how came they there?

It was before the days of much geological knowledge, but Pliny Moody exercised a common-sense method of explaining what he saw; for he concluded that these markings were made by some animal in an early period of the earth's history. Nothing was more natural to him than to surmise that they were made during the earliest aqueous deposit of which he had heard—the muddy sediments left by the Noachian Deluge. Hence he pointed out these foot-marks to his friends—the specimen being utilized for a stepping-stone at his front-door as having been made by Noah's raven when wandering in search of dry land. The slab is still preserved, and the impressions appear to have been made by one of that remarkable group of animals which abounded in New England during the Triassic or New Red Sandstone period.

Thirty-five years later, as Mr. W. W. Draper, of Greenfield, a village thirty miles farther north, was returning home from church, his attention was arrested by the sliding of snow from some large paving-stones leaning against a fence. As he turned his eyes, he saw a row of apparent ornithic impressions on the slab, shown very distinctly on account of the reflection of the sun's rays from a wet surface. A