Collyrium stamps, objects used to mark eye medicines, are more commonly found in Gaul than any other Roman province. Since they appear after Roman occupation, it is believed they evince a spread of Roman medicine, but this idea is not well-supported. Through a detailed study of the collyrium stamps it is apparent that the stamps took on other functions beyond marking remedies. They were used as amulets and votive offerings, signified by the fact that most are made of steatite and schist, almost all are green – a colour associated with eye care, and a number are decorated with magical symbols, and also by their context. Ultimately, the manner in which they were used demonstrates an adaptation of Roman material culture to fit the practices and beliefs based on earlier Iron Age traditions in the region.

Agricultural productivity and Amazonian settlement

The nature of Pre-Columbian agricultural systems in Amazonia has stimulated considerable debate, specifically: can one or another cultigen — maize or manioc — provide a stable agricultural base for sedentism and population growth (eg. Carneiro 1961; 1986; Gross 1975; Meggers 1996; Roosevelt 1980)? Certain ecological factors are generally seen to limit production and intensification of those subsistence resources that can support sedentary or densely distributed populations. Low agricultural productivity, characteristic of many Amazonian soils, and the generally low density and patchy distribution of terrestrial game are commonly cited as limiting factors (Gross 1975; 1983; Johnson 1982; Meggers 1954; 1996; Ross 1978; Sponsel 1989). It has become accepted that the highly restricted váirzea regions, primarily the floodplain settings of the major ‘white-water’ rivers (the Amazon and its Andean-derived tributaries), did not impose these environmental constraints on demographic or economic growth due to their fertile soils and higher concentrations of rich aquatic resources (e.g. Brochado 1984; 1989; Carneiro 1986; 1995; Denevan 1996; Lathrap 1968; 1970; 1987; Lathrap et al. 1985; Meggers 1996; Moran 1993; Roosevelt 1980; 1989; 1994).