insisted that he could put his hands on anything he wanted and heaven help the person who disturbed his mess! Mindful of this, Patty gingerly lifted a sheaf of papers from the only remaining chair and held them in her hand as she waited, making a mental note to replace them when she left.
At last Welton looked up from the object in his hand. “What would you think of this, my dear?” He held out toward her what looked to be an ordinary slab of stone.
“Why, I don’t know, it looks like just an old rock to me,” she answered. “That’s not a very scientific answer, I admit.”
“I quite agree.”
“I’m sorry, but we didn’t learn too much about your branch of science in school, Welty. Mostly chemistry and biology, you know.”
“To be a daughter of mine, you’ll have to do better than that.” Patty smiled happily at the relationship he had implied. “Now,” Welton cleared his throat and assumed the voice of a platform lecturer, “this is a specimen of petrified wood. You know what that is, don’t you?”
“No, sir,” came the answer in a small voice matching that of a timid schoolgirl.
“Petrified wood is wood that—I—well—that is petrified, of course. Everyone knows that.”
“Do you mean wood from a tree that has had the small particles of cellulose replaced by grains of minerals until gradually, over a period of thousands of years, the tree has turned to stone?
A hearty laugh reverberated in the room and reached even Mavis and Jo in the bedroom beyond. “Well, well, the joke’s on me this time.” Welton pulled out his handkerchief to wipe the tears from his cheeks.
“To be honest with you, Welty, it only just happened that I found one of your books fallen behind the radio last night and after I had fished it out I started to leaf through it. Then I got so interested that I read quite a lot of it after I went to bed. You can ask Jo about that, because she was mad at me for leaving the light on so long.”
“Hmmm, so you found the subject interesting, eh? Well, we’ll see about that. Now, to what do I attribute the honor of this visit? In short,” he added pompously, “what did you want?”
“Oh,” Pat answered hastily, “Mavis needs some paper and a pencil. She said you’d have some we might use.”
“Of course, here you are.” And, confidently opening the top drawer of the desk, he felt around for the desired articles. He took his hand out again after pushing a few things around and looked bewildered. Then his eyes roved the desk top. “Ah.” He picked up one of the pencil stubs and reached under the tallest stack of papers for a torn piece of an old manila envelope. “Will these do?”
“Okay for a shopping list, I guess. Thanks.” Pat blew him a kiss as she retreated to the doorway. “Oh, gee, I almost forgot. Here.” She returned and laid the papers she was holding in her hand back on the chair.
“Ten minutes to find these?” Jo asked Pat, wrinkling her nose at what she considered shameful tardiness.
“We got to talking about something else,” Pat retorted vaguely.
“This will be fine,” Mavis laughed. “I know what happened. Welty got off on his favorite subject. Maybe I had better head this list with a set of scratch pads for myself!”
“Sometimes I wonder how he got along so long without us, don’t you?”
“Stop thinking so hard and help me with this load of your sweaters,” Jo chided her.
Pat fell to work with a will and soon order was again restored. Mavis finished her list and was rechecking it when Welton looked in from the hallway.
“Anyone here interested in a little tramp through the woods? Can’t seem to settle down to work today. Nothing clears the mind like a good walk in fresh air.”
“That’s for me,” Jo said, groaning a little as she straightened up. “All morning that glorious sunshine has been fairly begging for a sympathetic soul like mine to take advantage of it.”
“Maybe we could help you, Welty.” This came from Pat. “That is, if you’d let us. Wouldn’t we, Jo?”
“Gee whiz, sure. The only trouble is we don’t know one fossil from another. At least, I don’t. Here, catch.” She picked up a sweater for herself from the bed and tossed another one over to Pat.
The two girls just stood for a moment on the top porch step when they first went outside. The garden was ablaze with color, intensified by the bright sunlight, but a cool wind blew across the lake and they were glad they had remembered to wear sweaters. The breeze gently pushed the branches at the tops of the tall trees overhead, as the party of four walked along through the woods. It was the same trail that the Faradays had followed six months before, although then it had looked quite different. Had it not been for the hunting shack which they both recognized as Welton’s “hideout” the girls would have found it difficult to believe. Squirrels and many varieties of birds put forth a noisy chatter high over their heads. At the level of their feet they could detect the scurrying sounds of what were undoubtedly rabbits and other small game.
Presently the group came to the banks of a small river and stopped. “Since you’ve expressed such an interest in my work, we might just as well have our first lesson in geology this morning. Right here beside this river is a good place to begin.”
“Why, Welty?” asked Pat, coming closer to the edge of the river bank. “I don’t see any interesting-looking rocks here.”
“Perhaps you don’t, Patty, but do you know what an important part rivers play in the formation of rocks?”
She and Jo both shook their heads.
“Millions of years ago when the earth was formed, it was hot. Gradually it cooled and shrank and in this cooling process the earth buckled in some places to form our great mountain systems. Next came the formation of water—seas, lakes and streams. These small streams at first just ran along the top of the earth until they managed to carve out beds to flow in. Next they widened the beds, taking earth from the sides and depositing it on the bottom or perhaps even carrying some of it all the way to the sea. Layers and layers of small grains of earth, or sediment, gradually came to be deposited in this way. And do you know what happened then?”
“You did say this had something to do with the formation of rocks,” Jo said slowly, “but I’m not sure I see the connection yet.”
“Yes, it does have a great deal to do with rock formations. You see, after the winter snows melted, sometimes these streams we are talking about became swollen and overflowed their banks. When that happened the stream often did not go back into its old course, but, instead, it carved out a new bed. As a result the banks of the old stream were covered with earth and the sediment was pressed down hard. Years and years later rocks had been formed. That is how sandstone and limestone and shale are made. We classify them all as sedimentary rocks.”
“I see, sedimentary because they are made from sediment. Is that it?” Pat’s face wore an intent look.
“Is this same process taking place right now?”
“It is. Although it will take millions of years and just the right sort of conditions for the sediment deposited by this river to become
