It's a book on wildlife for North America, in particular. This city might not actually be in North America, but it's what Corwin would have had in his old, pre-Hex life. He flips it open to the back, where the section on mammals is, showing her the pictures, brief blurbs on behaviors, and most importantly, drawn images of their tracks. "See? You compare signs left behind by whatever the animal is to these, and you can make a guess as to what they are."