"Ancient trail blaze," he said. "All this is unmapped wilderness, yet somebody found the way through here before us—many years ago."
"Who? When?"
"I don't know. Some old-time explorer, perhaps. The tree probably has added many inches to its girth since that mark was entrusted to its keeping."
The girl moved forward to inspect the tiny line that was no more than a slight puckering of the bark. "You mean—that's a blaze—left there by somebody?"
Dexter nodded. "A fresh ax cut first glazes itself over with a film of pitch," he said. "Then the bark begins to draw itself together, and finally covers the wound. The annual rings of growth add their covering year by year, until the original scar is buried deep in the wood. In the end nothing is left to show what had happened, save a tiny wrinkle in the bark. But the mark itself is never lost, even if the tree should live for hundreds of years. Let's see."
He unbelted his keen bladed ax, and yielding the tool with his left hand, he began to chop into the sapwood, first above and then below the time-healed scar. In a few moments he was able to split out a long, thick slab; and with tense interest he leaned forward to see what might lie underneath.
"Look!" he exclaimed.
On the surface of white wood exposed, faint characters were discernible. He made out the carved tracery of a letter "W," and there were other lines that he could not quite decipher. For a moment he peered at the section of scribed wood, and then quietly nodded his head.
"I never heard of surveyors going through this part of the wilderness," he observed musingly, "yet this looks like a surveyor's line tree." He counted the growth rings, and looked with thoughtful eyes into the shadowy stillness beyond. "More than half a century ago some man passed through here and cut his blaze and left direction marks behind him," he said in a hushed voice. "The man probably is dead, and I don't suppose he ever knew that he had rendered a service to a later generation of the Canadian mounted."
"What do you mean?" asked the girl wonderingly.