Danny Dunn and the Fossil Cave

Wherever hew is, whatever he does, Danny Dunn manages to attract scientific adventure without even trying. Excitement is the least to be expected when Danny stumbles on the entrance to a cave. Then a visit from Dr. Tresselt, the geologist, coincides with the completion of Professor Bullfinch's latest invention, the C-Ray. With a cave to explore, a scientific authority on hand, and a machine that can see through rock to be tested, Danny is ready for action - and so are Irene and Joe, who make up the rest of the party. But when Danny and his friends find themelves trapped inside a mountain of rock, what an expedition it turns out to be! Here are fun and speleological adventure for Danny Dunn's fans. As with all the earlier Danny Dunn stories, boys and girls will laugh while they learn with Danny Dunn. --- from book's dustjacket