I did enjoy the [CCNY geology] field trips. We went upstate and clambered over formations of synclines and anticlines. We had to diagram them, and figure out their mirror images. If you had an anticline here, you should be able to predict a complementing syncline bulging out somewhere else. Very satisfying when I got it right. Geology allowed me to display my brilliance to my non-college friends. 'You know, the Hudson really isn't a river.' "What are you talking about? ... Everybody knows the Hudson River's a river.' I would explain that the Hudson was a 'drowned' river, up to about Poughkeepsie. The Ice Age had depressed the riverbed to a depth that allowed the Atlantic Ocean to flood inland. Consequently, the lower Hudson was really a saltwater estuary.[Powell graduated with a B.S. degree in Geology.]