Old Jefferson, which looked so near, wasn’t so near as it looked, of course. Mountains never are. They descended gradually from Minto Pasture, through a “ghost forest” for two or three miles. A ghost forest is a forest which has been burned, without consuming the standing trunks. There the trees stood, thousands of them, but ghostly gray and dead—not a live branch, not a needle. Beyond this forest, they came out on a great plateau three miles wide, which was bare of everything except low bushes, wild flowers, a few snow-drifts and lava heaps, and a tiny brown tarn of water. The fire had done its work thoroughly here.
“Grizzly Flats, they call this,” Norman said. “But I guess it’s been a long time since any grizzlies were seen here.”
“What a fire this must have been!” Spider was saying, when Bennie suddenly cried, “Sh!”
“What is it?”
“Somebody’s following us over the trail on a motorcycle,” he answered. “Don’t you hear?”
It certainly sounded that way. Far off they heard the roaring buzz of an unmuffled engine.
“An aeroplane!” Spider exclaimed.
They halted, listening and watching. A moment later, flying fairly low, the plane came over Minto Mountain behind them, and swept toward Grizzly Flats. As if he saw them, and wanted to tell them so, the aviator swooped a bit over their heads, then rose again, banked against the white wall of Jefferson, and swung off to the north.
“What is he doing here?” the boys exclaimed.
“It’s one of the new aeroplane forest patrol,” Norman said. “They go out every day now, in the dry season, to spot fires. We haven’t had a bad fire—not one of the old-fashioned big blazes, since they started in. They can get up and see into all the cañons, everywhere, every day, and get back with the tip in no time.”