Cal stared intently, for the shadows were beginning to deepen, and he knew that he would be interfered with if he went too far in his first ramble. The stone tank did not contain all the masonry over which the dead tree was leaning. The mound itself arose four-square.
"It's one of those Mexican pyramids," exclaimed Cal. "I've read about them. Didn't know that any of them were ever found away up here."
He may or may not have been correct about that, but in a moment more he turned to Crooked Stick.
"Sun go down?" he asked.
"Ugh! No. Pull Stick get heap water."
The deepening of the shadows had not been altogether because that notable day of Cal's life had nearly gone. It was rather because black masses of thunderclouds had suddenly arrived, and had hidden all the sky above that part of the ancient Aztec forest.
Swiftly enough came a darkness that walked in among the tree-trunks and covered them so that they could not be seen at twenty feet away.
A vivid gleam of quivering lightning made everything stand out clearly for a second. Then came a deafening roll of thunder, and that was followed by another burst of sound that Cal did not recognize. He did not even know the Apache word for cougar, which sprang to the lips of Crooked Nose. The beast which had uttered the terrified roar, however, came leaping past with tremendous bounds, as if the thunderbolt had fallen near him and he hoped to get away from it. Cal stood still, mainly because no time was given him for doing anything else, but the cougar almost brushed his shoulder as it sprang by him.
"Ugh!" said Crooked Nose. "Pull Stick great brave by and by. Good!"
Flash after flash, almost incessantly, followed the tremulous glare of lightning, and peal on peal followed the thunder, during a full minute, before any rain fell. Then it seemed to Cal as if one awful flash went through everything around him, bringing its rattling volume of deafening thunder with it. He was half-blinded, half-stunned, for a moment.