Cornovii (Cornwall) Dumnoniorum (present day Exeter), it is likely that he only listed Roman places, not purely native sites. Of these, there has been speculation that Voliba might be a place in Cornwall and Tamara is assumed to be on the River Tamar, the border between Cornwall and Devon. Ptolemy's list is supplemented by the problematical Ravenna Cosmography, which lists sixteen names before Isca Dumnoniorum (which is listed as "scadum namorum", showing some of the problems of this source) and which have therefore been assumed to be west of Exeter. Several have been identified as most likely in Devon, leaving "purocoronavis" (the
Insula (Roman city) Insula (Roman city) An insula (Latin for "island") is a city block in an ancient Roman city plan, i.e. one that is surrounded by four streets. The term was also used for apartment buildings that took up an entire city block. A standard Roman city plan was based on a grid of orthogonal streets and was probably founded on the ancient Greek model of Hippodamus and was used when new cities were established, e.g. in Roman coloniae. The main streets of each city would be the Decumanus Maximus (east–west-oriented) and Cardo Maximus (north–south) which intersected at, or close to, the