“You can probably do that,” the scientist replied. “I had planned to start for the west in a couple of weeks.”
“Whereabouts?”
“I want to correlate some horizons,” was the reply.
The boy looked puzzled.
“You don’t see what I mean?” the professor asked.
“I don’t, quite,” the lad replied.
“Well, Perry, I want to visit three or four points in Wyoming where different strata of rock are exposed, working from the Upper Eocene downwards. You remember, at the Fayum, there were rocks belonging to the Oligocene Period right up at the top of the cliff, Upper Eocene on the next layer, Middle Eocene where we had our camp, and Lower Eocene down near that Birket-el-Qurun lake?”
“You bet I remember,” said Perry, “why, Uncle George, just for fun I made myself a model of it.”
“Good thing to do, it’ll help you to remember. Now, in the States we haven’t any one place where all these various strata show up clearly one above the other, with great ledges exposed for exploration and working, as they are in the Fayum. But, all over Wyoming, in different valleys and at different parts of the Bad Lands, there are these same strata exposed for miles and miles. At one place, Perry, such as the Washakie formation, where I’m going first, all the rocks deposited since the time of the Upper Eocene Period, have been washed or weathered away, so that the Upper Eocene layers are exposed. It’s a Bad Land country, too, where the rocks are soft, where there is no fertile soil and no steady rainfall. So, when the cloudbursts come, the rain eats easily into the soft rocks and carves them into buttes and ravines. The sand-bearing winds cut them away still further, so there are hundreds of thousands of square feet exposed to the weather and erosion is always going on.”
“Gee, what a chance!” cried Perry. “Why, you could go over a country like that every year and find something.”