The role of abductive reasoning in science has recently received much attention in the domains of Artificial Intelligence and Cognitive Science. Abduction, as characterized by the philosopher Charles Peirce, is both a form of logical inference, one complementary to deduction and induction, and also a "logic of discovery", an initial stage of inquiry in which scientific explanations of anomalies are constructed. Work to date on the theory and modeling of abductive logic has concentrated on verbal abduction--that is, abductive reasoning with wordlike representations of information. One way of generalizing this work is to examine the use of visual representations of information. Psychological and biographical evidence suggests that people do use visual representations, i.e., visual mental imagery, when engaged in certain cognitive tasks. The likelihood that visual imagery plays a role in abductive reasoning makes visual imagery a natural subject of research in Cognitive Science. One significant kind of visual representation was classified by Peirce as iconic, meaning a representation of an object that maintains properties of its appearance, such as shape or spatial structure. Explanations as to the causes of the shapes and spatial structures play an important role in the conduct of certain scientific pursuits, such as physical anthropology and archaeology. Clearly, the role of visual abductive reasoning in these sciences must be appreciated if a proper understanding of them is to be attained. This paper outlines work in progress (Shelley, 1994) which characterizes visual abductive reasoning and examines its role in the domain of archaeology. Section 2 gives an introductory discussion of the nature of "verbal" abduction, while section 3 presents an examination of visual abduction and some examples of it taken from the anthropological literature. Section 4 presents conclusions that may drawn from work done so far, and describes the computational modeling that needs to be done to support these conclusions.