The mighty portal to which this tablet formed the keystone, was only partially the work of man. Here the elemental forces that originally hollowed out the great central chamber through which the explorers had passed, had encountered a granitic rock effectually resisting their ravages. Hence, the narrowing of the passage-way to the diameter of the half-circle described by the white arch, and hence the opportunity that had been seized by an aboriginal race of men to complete and embellish what nature had so nobly planned. The sides of the arch rose in majestic columns, shaped and smoothed to the semblance of such pillars as those used in the massive temples of ancient Egypt; and, still bearing out this similarity, each of these pillars stood at the head of a long row that stretched away indefinitely in the darkness beyond. The curve of the arch overhead had also followed the simplest of lines, but with so glowing a symmetry that the beholder yielded to the conviction that here, whether of Nature's design or Man's, he stood on the threshold of a realm wherein were garnered treasures of art and science unique in the world's history. Besides the golden characters engraved on the keystone of this gigantic portal there was but one attempt at sculptural adornment. This was the rudely carved head of a condor, made to curve downward from the central tablet of the arch, as if the sleepless duty had been given to this winged monarch of the Andes of inspecting all who passed beneath its lofty eyrie. Before this imposing structure the explorers paused in astonishment. Anitoo smiled, somewhat disdainfully, and signed to them to enter. This they were loath to do until they could learn more definitely whither the cavemen were leading them. "Senores," remonstrated Anitoo, "when you were lost in this cave, I came to your rescue. Now, you must follow me." "That is very good," said Miranda irritably. "We have enough of this cave. We want to go out." "Follow me," persisted Anitoo. "You take us out?" "I take you to the queen," he retorted. "Why we go to your queen? We make nothing with your queen." "Ah, but perhaps she make something with you." "Caramba! What she make with me?" "You will see." The explorers looked at each other helplessly. One thing was evident--the Indians had no intention of parting with them. But they could not tell whether they were hostile or friendly. They were not treated as captives; but they felt that any attempt to escape would be quickly frustrated. They were too far outnumbered by the cavemen to make resistance possible. Leighton therefore decided that there was nothing for it but submission. Upon this the Indians gave a grunt of satisfaction, and Anitoo signaled to advance, pointing upward to the Sign of the Condor. But the signal came too late.