need help finding title of a book i read as a teenager

Grade 5-9 Needing a place to hide from a group of vicious classmates, Barney Pennimen joins secretive Snowy Cobb to explore a hidden cave in which a small, unidentified bone was found. The boys find traces of a miniature villagebut are not sure whether it is a model of a community or the actual remains of a 100,000-year-old civilization. Wells tells two stories here: Barney's victimization and growing strength of character, and the boys' discovery and protection of the ancient civilization. Both are suspenseful and remarkably well integrated into the novel. Obsessively private Snowy, who has emotional problems, and Barney, an intelligent boy whose past submission to peer pressure has gotten him into trouble, are both fully realized characters. These two will engage readers' interest, which will be sustained throughout by the brutal reality of Barney's school experiences and the appealing fantasy of the boys' remarkable findings. The wish fulfillment associated with that discovery will more than compensate for the minimal or non-existent scientific and historic groundings of the civilization and its unearthing (a society of six-inch humans does not fit in with evolutionary theory; the achievements of their civilization does not match cultural history; it is implausible that two boys could have the archaeological know-how to uncover the village without harming it). An absorbing school story with a twist, this one is sure to fill readers with a sense of wonder. David Gale, ``School Library Journal'' copyright ybarra-cgm
Copyright 1987 Reed Business Information, Inc. --This text refers to an out of print or unavailable edition of this title.

Barney's life is a mess. Everyone thinks he's a snitch. His former friends want to kill him. Even the headmaster of his school wants him gone. No one but secretive little Snowy Cobb will speak to him. But after Snowy and Barney discover the hidden cave deep below the earth, the promise of ancient treasures wipe away the threats from above. And when they uncover strange artifacts untouched for centuries, a web of unknowable danger begins to unravel-and Snowy and Barney may not survive."