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
Southern England Chalk Formation Southern England Chalk Formation The Chalk Formation of Southern England is a system of chalk downland in the south of England. The formation is perhaps best known for Salisbury Plain, the location of Stonehenge, the Isle of Wight, and the twin ridgeways of the North Downs and South Downs. The North Downs are confined chiefly to the counties of Kent and Surrey, and the South to Sussex. Each forms a well-defined long range springing from the chalk area of Dorset and Hampshire, to which, though broken up into a great number of short ranges and groups of hills, the general