The Dinosaur Mystery by Gertrude Chandler Warner

close on purpose when he saw us,” Jessie said.
    By the time the children made their way up to Dr. Pettibone’s office, they were completely out of breath. Again, they saw a light under the door of the fossil lab.
    â€œDr. Pettibone? Dr. Pettibone?” Violet called out. “We came back to help you.”
    Dr. Pettibone stepped out of the lab. He greeted the children as if he had not seen them by the elevator just minutes before. “Did you have a good lunch?”
    â€œYes, we did,” Violet answered. She handed him a lunch bag. “Mr. and Mrs. Diggs sent you a lunch, too.”
    Dr. Pettibone took the bag and smiled at the children nervously. “Well, thank you … uh … thank you very much for bringing this. Now step inside the lab here, and I’ll show you how to label some of my fossils for display.”
    The children looked at each other, surprised to be invited right into the lab. Several workbenches were lined up in the middle of the room. On one of them were trays of small tools — picks, drills, small hammers, chisels, and magnifying glasses.
    â€œOur dentist has some tools just like those,” Violet observed.
    Dr. Pettibone picked up a small drill. “That’s exactly right, Violet. Watch how we use one of these.”
    Dr. Pettibone walked over to one of the other workbenches where several chunks of rocks were arranged. He picked up one of them and began to drill.
    â€œOuch!” Henry said. “I hate that noise. It reminds me of getting a cavity filled.”
    Dr. Pettibone laughed. “Well, this is a similar process. I’m drilling the rock away to expose something inside.”

    â€œWhat’s in there anyway?” Violet asked.
    â€œA dinosaur joint,” Dr. Pettibone answered over the sound of the small drill. “One of my field assistants spotted part of a fossil sticking out of the ground at one of our sites out in Wisconsin a few months ago. She dug it but left plenty of rock — which we call the matrix — around it. Then she wrapped the whole thing in a plaster cast much the way you’d put a broken bone in a cast to protect it. These pieces already have the plaster removed and most of the matrix. You’ll see the rest of the fossil in just a bit.”
    Henry and Violet were so fascinated by what Dr. Pettibone was doing, they didn’t mention anything at all about seeing him in the elevator. Only Jessie couldn’t stop wondering about where the big crate was. Had Dr. Pettibone brought it back to the office? While she followed what he was doing, she also glanced around the room. There was no crate to be seen.
    The drilling stopped, and Dr. Pettibone held up a thick object and put it under a bright light. “There’s still some rock matrix next to the bone that will have to be chipped off very carefully. The drill might damage it at this point. Only someone with steady and delicate hands can do the next step.”
    Henry looked at Violet, then he looked at Dr. Pettibone. “Did our grandfather or Mr. and Mrs. Diggs ever tell you that Violet plays the violin and is an artist? She has very good hands for delicate things.”
    â€œSo I’m told,” Dr. Pettibone said. “That’s why I picked this out for her.” He turned to Violet. “Would you like to begin work on this joint by chipping away some of the rock? Not all the way, mind you, but some of the outer layer.”
    Violet gave Dr. Pettibone her sweetest smile. “Yes, I would like to give it a try. Thank you for asking me. I’ll be very, very careful.”
    â€œWhat can we do, Dr. Pettibone?” Henry asked. “Do you have anything heavy I can move for you? Boxes or crates or anything?”
    Dr. Pettibone stared hard at Henry but didn’t answer the question. Instead he said, “Come over here, and I’ll show you what needs doing.” Dr. Pettibone waved Jessie and Henry over to the workbench