Page:Popular Science Monthly Volume 66.djvu/145

Rh are those of an unknown tongue, the meaning of which is an enigma unless one has the key. The earlier students attempted to decipher the footprints by comparing them with animals then known, with the

result that they thought they recognized the impressions of batrachians, reptiles, birds and mammals; in fact every group of creatures which were

capable of making tracks. It will be seen at once that the only true key to these nature's hieroglyphics would be actual skeletal remains associated with the footprints or, if found elsewhere, in beds of equivalent age.