“I have to ask your pardon, Mr. Haynes,” he said. “Your drawing was faithful.”

“But what in Heaven’s name does it mean?” cried Dick Colton.

“It means that we are on the verge of the most important discovery of modern times,” said the professor. “Savants have hitherto scouted the suggestions to be deduced from the persistent legend of the roc and from certain almost universal North American Indian lore, notwithstanding that the theory of some monstrous, winged creature widely different from any recognised existing forms is supported by more convincing proofs. In the north of England, in 1844, reputable witnesses found the tracks, after a night’s fall of snow, of a creature with a pendent tail, which made flights over houses and other obstructions, leaving a trail much like this before us. There are other corroborative instances of a similar nature. In view of the present evidence, I would say that this unquestionably was a pteranodon, or a descendant little altered, and a gigantic specimen, for these tracks are distinctly larger than the fossil marks. Gentlemen, I congratulate you both on your part in so epoch-making a discovery.”

“Do you expect a sane man to believe this thing?” Haynes demanded.

“That’s what I feel,” said Everard Colton. “But, on your own showing of the evidence, what else is there to believe?”

“But, see here,” Haynes expostulated, all the time feeling as if he were arguing in and against a dream. “If this is a flying creature, how explain the footprints leading up to Serdholm’s body, as well as away from it?”

“Owing to its structure,” said the professor, “the pteranodon could not rise rapidly from the ground in flight. It either sought an acclivity from which to launch itself, or ran swiftly along the ground, gathering impetus for a leap into the air with outspread wings. Similarly, in alighting, it probably ran along on its hind feet before dropping to its small fore feet. Now, conceive the pteranodon to be on the cliff’s edge, about to start upon its evening flight. Below it appears a man. Its ferocious nature is aroused at the sight of this unknown being. Down it swoops, skims swiftly with pattering feet toward him, impales him on its dreadful beak, then returns to climb the cliff and again launch itself for flight.”

All this time Haynes had been holding one of the smaller rocks in his hand. Now he flung it toward the gully and turned away, saying vehemently: “If the shore was covered with footprints, I wouldn’t believe it! It’s too—”

He never finished that sentence. From out of the darkness there came a hoarse cry. Heavy wings beat the air with swift strokes. In that instant panic fell upon them. Haynes ran for the shelter of the cliff, and after him came the Coltons. Johnston dropped on hands and knees and scurried like a crab for cover. Only the professor stood his ground; but it was with a tremulous voice that he called to his companions:

“That was a common marsh or short-eared owl that rose. The Asio accipitrinus is not rare hereabouts, nor is it dangerous to mankind. There is nothing further to do to-night, and I believe that we are in some peril remaining here, as the pteranodon appears to be nocturnal.”