Isaca
Isaca in Britain, a river mentioned by Ptolemy (2.3.4) as lying west of the outlet of the Tamarus (Tamar). In the Monumenta Britannica, Isacae ostia are identified with Weymouth, and also with Exmouth; most probably the latter, name for name, as well as place for place. In the Geographer of Ravenna the form. is Isca, which is preferable. [ISCA]
From William Smith (ed.), Dictionary of Greek and Roman Geography. Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities and Tufts University. Data accessed from https://github.com/PerseusDL/canonical-pdlrefwk/ on 17 October 2026.