Frog--and Science Hero--Professor Albert Hopper travels with his niece Polly and nephew Tad to the center of the Earth, encountering prehistoric cavefrogs, dinosaur fossils, and Yeti on the way.
year: 2020
call number/section: 1000
subjects: frogs, juvenile fiction, scientists, voyages and travels, adventure stories, fiction, adventure and adventurers, adventure fiction, earth (planet), core, juvenile fiction, fiction, earth, action and adventure fiction