This study is part of a project for Patapsco Valley State Park. Is it a complete comprehensive study? Not by a long shot. It is the best collection of this type of information available at this time. It is a study built upon information based in it's bibliography. There is still much to do. When asked how much time it took? I say forever! It never ends! As soon as I finish a section new material seems to surface. I regularly get telephone calls asking, adding or correcting materials. If pursued I would say about eight hours of research per mile to cover both our 1993 and 2003 studies.