"It is when a prospector strikes a section where all the gold-bearing rock has been eroded that he is apt to find the 'pockets' so dear to his heart. The amazing riches of the Klondyke lay in the fact that prospectors found, first, the alluvial deposits from the present age in the sands of the running creeks, and, on ledges high above the creeks and running into the rocks on either side, the alluvial deposits, even thicker and richer, of a bygone time."
"You've got it right," declared Jim, emphatically. "I know 'cos I was there!"
"Was it on the Yukon, then, that you made your famous strike?"
The prospector winced. Evidently, he intended to reach that point in his own way.
"I'll tell you about that, after a bit," he answered evasively. "But you ain't said why placer claims peter out."
"Can't you see? A placer claim doesn't show where the big store of gold is, but where it isn't! It shows that the gold has gone. A placer is just a spot where a little heavy gold, that hasn't been acted on by chemicals, happens to have been deposited during the erosion of a mountain which was composed of gold-bearing rock. The rock has been washed into sand and gravel and a great deal of it taken out to sea. There's plenty of gold in the sea, as I told you before.
"But the amount of sand or gravel to be panned along a creek or river is limited. When that's washed over, there's no more to find. A prospector gets down to bed-rock and he's through. Then he's either got to pack up and hunt some new spot where the same erosion has happened, or, if he's clever enough, he's got to find the rock or reef from which the gold was washed out. If he doesn't know his geology, he's apt to waste his time.
"Then the scientific expert and the capitalist come in. It's the man with money who profits most by a poor man's strike. He can afford to sit back and wait. Presently the expert will come back and report where the gold-bearing rock lies. The capitalist arrives with huge machinery for mining and crushing the rock, for turning on enormous water-power, in short, for performing a sort of artificial erosion in a few days which Nature took hundreds of thousands of years to do. He pockets millions, where the prospectors who did the first work only get thousands, or even hundreds, or, sometimes, nothing at all.
"Your father was perfectly right, Jim, in saying that the prizes of prospecting are for the man who gets there first. Placers are bound to peter out quickly. They are Nature's purses, and a purse hasn't any more money in it than you put in. Even the Klondyke, that astounding pocket of riches, lasted only three years and then dwindled down.
"Some of these days, all the available places of the earth will have been worked over by the casual prospector, and then his day will be done. The ever-hoping rover of the pick, shovel, and pan is becoming extinct. Even now, the only spots which hold out any chance of pockets of gold are in the almost inaccessible section of the globe.