Inside one of the larger adits at the Indian Girl Mine near Hornbrook, California.  A former gold mine, there are many surface diggings & rock walls outside as well as small openings to mines & prospects, this opening leading to just over 100 feet inside.  Within the mines, gold-bearing quartz veins are hosted in native greenstone.  Ceiling height here is about nine feet however parts of this adit involve some crawling (including the entrance).