The geologic story of the Teton country from the time the earth was new to the present day has been summarized. What can we learn from it? We become aware that events recorded in the rocks are not a chaotic jumble of random accidents but came in an orderly, logical succession. We see the majestic parade of life evolving from simple to complex types, overcoming all natural disasters, and adapting to ever-changing environments. We can only speculate as to the motivating force that launched this fascinating geologic and biologic venture and what the ultimate goal may be. New facts and new ideas are added to the story each year, but many unknown chapters remain to be studied; these offer an irresistible, continuing challenge to inquisitive minds, strong bodies, and restless, adventurous spirits. Most geologic processes that developed the Teton landscape have been beneficial to man; a few have interfered with his activities, cost him money, time, effort, and on occasion, his life. Postglacial faulting and tilting along the southern margin of Grand Teton National Park diverted drainage systems (such as Flat Creek, southwest of the Flat Creek fault on the south edge of the geologic map), raised hills, dropped valleys, and made steep slopes unstable. Flood-control engineers wage a never-ending struggle to keep the Snake River from shifting to the west side of Jackson Hole as the valley tilts westward in response to movement along the Teton fault. Each highway into Jackson Hole has been blocked by a landslide at one time or another and maintenance of roads across slide areas requires much ingenuity. We see one slide (the Gros Ventre) that blocked a river; larger slides have occurred in the past, and more can be expected. Abundant fresh fault scarps are a constant reminder that public buildings, campgrounds, dams, and roads need to be designed to withstand the effects of earthquakes. Some of these problems have geologic solutions; others can be avoided or minimized as further study increases our understanding of this region. Man appeared during the last one-fiftieth of an inch on our yardstick of time gone by. In this short span he has had more impact on the earth and its inhabitants than any other form of life. Will he use wisely the lessons of the past as a guide while he writes his record on the yardstick of the future? APPENDIX Acknowledgements