1. History of continental drift \& plate tectonics a. What were Wegener's four lines of evidence for the continental drift hypothesis i. ii. iii. iv. b. What did Marie Tharp identify and how? 2. What do we see happening at mid-ocean ridges in terms of the rock types and ages? (you can refer to figure 1 to get a big picture view) Figure 1. Espinosa, Rinehart, Tharp map of global physiography with locations of seismicity. .