Two boys fall into a tunnel that leads them into a prehistoric world inhabited by saber-toothed tigers, giant dinosaurs, and other dangerous creatures. Original.
Miriam Schlein was an American author who wrote nearly 100 books that helped teach children about animals and more obscure ideas such as space and time. Her books include The Year of the Panda and Discovering Dinosaur Babies. Schlein died of vasculitis in Manhattan, New York, at age 78, in 2004.
Wow, this book took me forever to rediscover. I remembered a few bits and pieces of this story, but very little else, and a friendly stranger online was finally able to help me figure out what it was. It's a weird story about two kids who find a secret cave full of prehistoric creatures located in modern-day Bolivia.