RE: Geology questionI'm not a geologist and Geo:101 was surely one of my worst experiences in college, but in my readings in oil and gas exploration and talks with friends who are petroleum geologists my lay understanding is these formations tend to be areas of entrapment of a concentrated resource. This simple explanation from Wikipedia may shed more light: In geology, an anticline is a type of fold that involves a downward slope to either side. It is an upward-curved structure. In an eroded anticline the oldest rock layers are in the center and the rocks on either side dip or slope away from the center. Folds, and thus anticlines, typically form during crustal deformation as the result of compression that accompanies orogenic mountain building.