Book excerpt: Throughout Pennsylvania, within the state forest system, are 61 officially designated Natural Areas, each offering a bit of wildness deemed worthy of protection: rare-bird breeding sites, stands of old-growth trees, fragile wetlands, ice age remnants, mineral-rich mountainsides. To experience first-hand the unique features of each natural area, nature writer Charles Fergus spent a year visiting all 61. In this information-filled book, he reports on what he found, offering readers a guided tour of some of natural Pennsylvania's most distinctive places. He also provides information on how to visit the areas, each of which is open to the public.