ABSTRACT
There is a striking discrepancy between the way in which modern geologists communicate their ideas to each other, and the way the antecedents of these ideas are analyzed by historians. Whether in talks at conferences or in published scientific papers and books, modern geologists make extensive use of visual materials—maps, sections, colour slides, diagrams of all kinds. The development of the visual language of geology makes a particularly instructive case-study in the development of visual communication in science generally. It shared with other natural-history sciences a concern with configurations that could not be adequately conveyed by words or mathematical symbols alone. A modern geological map is an attempt to depict on a two-dimensional surface what cannot in reality be seen at all except in isolated exposures, namely the outcrops of rocks which are generally concealed by soil and vegetation. Like a geological map, a modern geological section is a highly theoretical construct.
