Yesterday I took an outing to one of my local mountains, and as usual I checked the geologic map beforehand. I make it my business to do this, but maybe you haven't gotten into the habit. Now the U.S. Geological Survey is making things easier for you in two ways. It serves topographic maps through the USTopo site, and it serves geologic maps through the new National Geologic Map Database, a one-stop source for stratigraphic names, a huge set of maps, a map viewer and a description of where mapping is currently going on. Don't leave home without them.