The Roman Map of Britain Durnovaranis vel Durnovaria Dorchester

Purocoronauis var. Purocoronains (R&C 6) NEXT
Durnonovaria var. Durnovaria (AI 483₆ Iter xii, by error of the copyist)
Durnonovaria (AI 486₁₅ Iter xv)

    The similarity of Purocornauis to Durocornouio Wanborough of AI Iter xiii has been long recognized. At Wanborough there were no Cornovii, but the brook there was recorded as Dorkerne 901 and Dorcyn 940.

    There is also a resemblance to Durnonovaria Dorchester of AI Iter xv. Durnonovaria is emended to Durnovaria which better agrees with the early forms Dornuuarana ceaster 847, Dornwaraceaster 864 and Durngueir ca.894.

    One might look at the first element of Purocoronauis as a corrupt Durnaco- 'site covered with fist-sized stones', later reduced to Durno- by the time of the Itineraries. And as with AI's Durnonovaria, we have what seems an extra syllable before -varia. 

    The Cosmography's form Purocoronauis can be explained by noting the later recorded form Dornuuarana ceaster. [The initial P for D error has been long recognized (compare Decuaria for Petuaria), and n for u is very common.]
    If the suspension mark abbreviating the n of Durno- was mistaken as an apostrophic vowel-r, we have a Duroro- read as Duroco; and -nauis for -uanis where an ambiguous apostrophic vowel-r (written ú) is misread -'uanis yielding -ronauis, rather than the intended -u'anis that would yield -uaranis; thus Durnovaranis.

Dorchester (SY6990)