Gary rolled the derrotero within the photograph and replaced them in his pack. He started down the slope to the floor of the gloomy canyon. Lobo stood still, then turned slowly and looked back along the way they had just traveled. He growled low and flattened his ears. The three explorers looked back. There was nothing to be seen. Lobo growled again.
Gary motioned to his two friends to take cover. He sank down behind a boulder and peered down the quiet canyon.
"What do you think it is?" hissed Tuck.
Gary wet his lips and felt for the field glasses. He focused them on the canyon and slowly swept every foot of it with the glasses. Nothing was to be seen, at least nothing that would threaten them.
"If that wasn't a rockfall that blocked us from getting back through that hole, and someone did block it, then mightn't they have waited until we left the cavern, then removed the blockage and followed us?" said Sue quietly.
Gary shrugged. He looked at Tuck. "You stay here with Sue and watch," he said. He handed Tuck his rifle and took the shotgun. "Don't do any wild shooting!"
Gary trudged down the slope, followed by Lobo. The dog kept looking back. Gary forced his way through a tangle of brush and then walked alongside the dry watercourse of the canyon. To either side, below the overhanging walls, were slopes of talus formed from the loose hanging rock that seemed ready to drop if one were to raise his voice in that echoing place. Thick and thorny brush had laced itself through the jumble. A snake would have had a hard time finding a way through the entanglements.
He rounded a curve and was a good half mile beyond the place where he had left his friends when the canyon widened. Here it was a mass of rock and brush through which the dry watercourse crept, almost turning completely back on itself at times. Sweat broke out on him as he forced his way through, grunting in pain as thorns pierced his clothing and flesh. He was finally forced to stop. He sat down on a flat rock and reached for his canteen. It was then that he saw the faint symbol carved into the opposite wall. He was on his feet in an instant, forcing his way across the tangle despite his weariness. He stopped on the treacherous slope below the symbol and stared at it. It was not familiar to him, although he lashed his flagging memory until his head ached. He then saw that the upper left and center part of the place where the symbol had been cut had flaked off through weathering. He half closed his eyes and then the realization came to him. The left-hand part of the symbol, as he faced it, should have been a reversed numeral 3, although in the case of this particular symbol they were not numerals, but rather brackets on each side of a word which was now incomplete. The complete symbol meant to stop and change direction.
Gary plunged down the slope, heedless of the thorny brush. He followed the rough bed of the old watercourse back along the canyon, studying each foot of the walls as he went along. He was almost back at the canyon junction before he knew it, and he had seen no further symbols.
Sue came down to him. "We haven't seen anything," she said.
"Forget about that!" said Gary. "Get Tuck!"
"Here," said the lean one as he came toward them. He eyed Gary. "You look excited, amigo. You see Asesino?"
Gary told them of his find. "We'll have to work to the other end of this canyon for more clues."
"What about him?" asked Tuck, jerking a thumb over his shoulder toward the canyon through which they had just traveled.
Gary whistled sharply for Lobo. He pointed to the narrow canyon. "Go, boy," he said. The dog trotted up the slope and vanished in the brush.
"No one will get past him," added Gary. "At least he'll let us know if anyone is around."
Gary led the way. They had walked a quarter of a mile when they turned a bend to find themselves looking at a thoroughly blocked canyon, filled with masses of rock and earth. There was no way under, around, through, or over that blockage.
"Crazy," said Tuck. "From what I figure, the canyon of the arrastres must be somewhere beyond that blockage. No wonder we couldn't find a way from there into here."
Sue was poking about with a stick. "Hey," she said. She picked up a rusted mule shoe, one of the type with the flared ends. "I wish this thing could talk."
"We'll have to work back," said Gary.
Slowly and carefully they scanned the walls until they reached the place where the narrow canyon joined the one they were in. Lobo dozed on a rock. "Well," said Gary, "that shows he didn't find anyone."
"Or whoever was in there went back," said Tuck.
They all looked at each other. The threat from the unknown was being far overshadowed by the thoughts that the mine must be somewhere close to them. "¡Adelante!" said Gary.
More than an hour passed. It was Tuck who made the next discovery, a rather curious symbol on a flat rock, almost completely covered by brush and a litter of gravel. The symbol was a stylized snake with the head pointing across to the western side of the canyon. There wasn't any doubt that the rock upon which it had been carved had been in that particular position a long time. They crossed the dry watercourse, for the symbol was plain enough. "Treasure on opposite side," it seemed to hiss.
The western side was a terrible jumble of rock with labyrinthine passages, some of them thoroughly choked with brush, weaving through the mass. The three of them examined every open rock face, then began to poke through the brush to examine others. Time drifted past and there were no new discoveries. Nothing but naked rock and cruel brush.
Tuck climbed a sloping rock ledge, then jumped down on the far side. There was a crashing sound and the hoarse voice of Tuck mouthing imprecations.
Gary grinned. He walked up the slope and looked down. All he could see was Tuck's head, the rest of his body was concealed by the ever-present brush.
"Anything down there?" asked Gary.
Tuck was still muttering. "Nothing but black dirt," he growled.
"Black dirt? In there?"
Tuck held up his hands. They were mottled black. "Well anyway, it's charcoal or something," he said.
Gary dropped on his belly. "Kick around a bit," he said.
Tuck's head vanished. In a few minutes it appeared like the head of a busy gopher. "Charcoal, all right," he said. "Seems like someone had a big fire in here."
"Gary!" called Sue from the other side of the ledge. "There's another hole here and the bottom is black too. Charcoal, I think."
"Eureka!" said Gary. His eyes widened.
"You loco or something?" asked Tuck.
"Charcoal, you dope! Charcoal pits were used by the old Spanish and Mexican miners to heat their drills so they could temper them! Man, we're close! We're so close!"
"There's another charcoal pit over here," said Sue. She paused. "Something else too! Another one of those snakes! Pointing right up this slope, Gary!" She popped out of the hole and pointed up the almost impassable slope toward the masses of rock clogging the western side of the canyon.
"We're almost right on top of it," said Gary in a hushed voice. "Up the slope! ¡Adelante!"