“Professor,” interrupted Haynes, “the only thing that approached Serdholm within striking distance walked on a foot armed with five great claws. You can see the trail on this map.” He produced a large sheet of paper on which was a crude but careful drawing. “And there is its sign-manual, life-size,” he added, pushing a second sheet across the table to the scientist. Imagination could hardly picture a more precise, unemotional and conventially scientific man than Professor Ravenden. Yet, at sight of the paper his eyes sparkled, he half started from his chair, a flush rose in his cheeks, he looked keenly from the sketch to the artist, and spoke in a voice that rang with a deep under-thrill of excitement: “Are you sure, Mr. Haynes—are you quite sure that this is substantially correct?” “Minor details may be inexact. In all essentials that will correspond to the marks made by something that walked from the mouth of the gully to the spot where we found the body and back again.” Before he had fairly finished the professor was out of the room. He returned almost immediately with a flat slab of considerable weight. This he laid on the table, and taking the drawing, sedulously compared it with an impression, deep-sunken into the slab. For Haynes a single glance was enough. That impression, stamped as it was on his brain, he would have identified as far as the eye could see it. “That’s it!” he cried with the eagerness of triumphant discovery. “The bird from whose foot that cast was made is the thing that killed Serdholm.” “Mr. Haynes,” said the entomologist dryly, “this is not a cast.” “Not a cast?” said the reporter in bewilderment. “What is it, then?” “It is a rock of the cretaceous period.” “A rock?” he repeated dully. “Of what period?” “The cretaceous. The creature whose footprint you see there trod that rock when it was soft ooze. That may have been one hundred million years ago. It was at least ten million.” Haynes looked again at the rock, and superfluous emotions stirred among the roots of his hair. “Where did you find it?” he asked presently. “It formed a part of Mr. Johnston’s stone fence. Probably he picked it up in his pasture yonder. The maker of the mark inhabited the island where we now are—this land then was distinct from Long Island—in the incalculably ancient ages.” “What did this bird thing call itself?” Haynes demanded. A sense of the ghastly ridiculousness of the affair was jostling, in the core of his brain, a strong shudder of mental nausea born of the void into which he was gazing. “It was not a bird. It was a reptile. Science knows it as the pteranodon.” “Could it kill a man with its beak?”