This study explains the Greco-Roman urban form as it relates to the geological basis at selected sites in the Mediterranean basin. Each of the sites--Argos, Delphi, Ephesus, and Syracuse among them--has manifested in its physical form the geology on which it stood and from which it was made. "By demonstrating the dependence of a group of cities on its geological base," the author writes, "the study forces us to examine more closely the ecology of human settlement, not as a set of theories but as a set of practical constraints..." Exacting attention will be given to local geology (typesof building stones, natural springs, effect of earthquakes, silting, etc.) The findings are based on site publications, visits to the sites, and the most recent archaeological plans...