Who is Brian McCarthy from Dragon Bones: A Novel and what is their importance?

Brian McCarthy is an American archaeological student. He is in China on a fellowship, which is attempting to preserve archaeological sites before the inundation from the Three Gorges Dam. Brian discovers a wealth of treasure in a cave, and begins bringing them to Lily Sinclair, one of the auctioneers for Cosgrove's. Additionally, he discovers proof of a large fungus, which he sends to his sister, as she is a mycologist.