“At least we’ll make a mighty big try,” said Ned, whose courage rose high at the sight of their natural fort.  They had their backs to the wall, but this wall was of solid stone, and it also curved around on either side of them.  Moreover, he had a chance to regain his breath which was once more coming in hot and painful gasps from his chest.

“Let’s lie down, Ned,” said Obed, “and pull up that log in front of this.”

Near them lay the stem of an oak that had fallen years before.  All the boughs had decayed and were gone, so it was not a very difficult task to drag the log in front of them, forming a kind of bar across the alcove.  As it was fully a foot in diameter it formed an excellent fortification behind which they lay with their rifles ready.  It was indeed a miniature fort, the best that a wilderness could furnish at a moment’s notice, and the fighting spirit of the two rose fast.  If the enemy came on they were ready to give him a welcome.

But the two heard nothing in the dense forest in front of them.  The pursuers evidently were aware of the place, in which they had taken refuge, and knew the need of cautious approach.  Mexicans do not lack bravery, but both Obed and Ned were sure there would be a long delay.

“I think that all we’ve got to do for the present,” said Obed, “is to watch the woods in front of us, and see that none of them sneaks up near enough for a good shot.”

Nearly an hour passed, and they neither saw nor heard anything in the forest.  Then there was a rushing sound, a tremendous impact in front of them and something huge bounded and bounded again among the bushes.  It was a great rock that had been rolled over the cliff above, in the hope that it would fall upon them, but the arch of stone over their heads was too deep.  It struck fully five feet in front of them.  Both were startled, although they knew that they were safe, and involuntarily they drew back.

“More will come,” said Obed.  “Just as one swallow does not make a summer, one stone does not make a flight.  Ah, there it is now!”

They heard that same rushing sound through the air, and a bowlder weighing at least half a ton struck in front of their log.  It did not bound away like the first, but being so much heavier buried half its weight in the earth and lay there.  Obed chuckled and regarded the big stone with an approving look.

“It’s an ill stone that doesn’t fall to somebody’s good,” he said.  “That big fellow is squarely in the path of anybody who advances to attack us, and adds materially to our breastwork.  If they’ll only drop a few more they’ll make an impregnable fortification for us.”

The third came as he spoke, but being a light one rolled away.  The fourth was also light, and alighting on the big one bounded back into the alcove, striking just between Ned and Obed.  It made both jump and shiver, but they knew that it was a chance not likely to happen again in a hundred times.  The bombardment continued for a quarter of an hour without any harm to either of the two, and then the silence came again.  Ned and Obed pushed the rock out of the alcove, leaving it in front of them and now their niche had a formidable stone reinforcement.