ABSTRACT
In 1793, William Smith, a British canal digger, recognized that rocks lay in different strata and that the fossils in those strata were different from one another. By 1815, he had dug trenches, mapped strata across Great Britain, and was rewriting geological understanding (Winchester 2002). As with most other things, the development of better understanding of geological forces and natural events proceeded from Smith’s work in ts and spurts. One of the coauthors of this book remembers that in the late 1940s, he suggested to his fth-grade school teacher that it looked very much as if the northeast coast of South America could t quite comfortably into the west coast of Africa and opined that the two continents may have been joined at one time. To his chagrin, she smiled condescendingly and said that it was just a coincidence. Her response reected conventional thinking at that time: to wit, the continents were xed in place and always had been but that “sunken land bridges” may have once linked some of them.
