CELTIC _OPPIDA_ AND FORTIFIED VILLAGES YORKSHIRE. Stanwick. NORTHAMPTONSHIRE. Hunsbury. KENT. Bigbury Camp. SUSSEX. Mount Caburn. BERKSHIRE. Northfield Farm, Long Wittenham. DORSETSHIRE. Hod Hill. Hambledown Hill. Maiden Castle. Rotherley. SOMERSETSHIRE. Ham Hill. NAIRNSHIRE. Burghead. PERTHSHIRE. Abernethy. AYRSHIRE. Seamill Fort. CARDIGANSHIRE. Castell Nadolig. CARNARVONSHIRE. Treceiri. ROMANO-BRITISH STATIONS AND TOWNS NORTHUMBERLAND. Great Chesters (Æsica). Risingham (Habitancum). WESTMORELAND. Brough. Kirkby Thore. LANCASHIRE. Ribchester. YORKSHIRE. New Malton. NORTHAMPTON. Wellingborough. SURREY. Farley Heath. HAMPSHIRE. Silchester. PERTHSHIRE. Ardoch. DUMFRIES. Birrenswark. A study of the above lists discloses some interesting facts. It will be noticed that the caves are confined exclusively to the limestone districts of the counties of York, Lancaster, Derby, Stafford, and Devon. The lake-dwellings are found chiefly in the south-west of Scotland and the north-east and central part of Ireland, there being only one example in England and none in Wales. The _brochs_ and _weems_ (or underground houses) are Pictish structures, and therefore do not occur anywhere except in Scotland, chiefly in its north-eastern counties. The Celtic _oppida_ are most common in the south of England where the Belgic settlements predominated, but there are a few examples in Scotland. Probably a more systematic examination of the hill-forts throughout Great Britain would show that those in which large areas are enclosed by double and triple ramparts of stone or earth[168] belong to the Late-Celtic period. At the present time practically nothing is known as to the age of the stone forts and earthen raths in Ireland or Wales. Most of the Romano-British fortified sites which have yielded works of art of Late-Celtic type, although executed under Roman influence, are in the south of Scotland or in the north of England, on or near the Wall of Hadrian, or along the lines of the military roads leading to it.[169] At Farley Heath, near Guildford, Surrey, numerous specimens of Kelto-Roman enamelled bronze objects have been found, and this site would no doubt produce a plentiful harvest of antiquities of a similar nature if properly explored. The great difficulty, however, as we have already pointed out in dealing with the Romano-British sites, is to determine to what extent the style of the art of the objects found there can be shown to be definitely Celtic. In our lists we have only included sites from which have been procured antiquities exhibiting Celtic enamel and flamboyant ornament, or fibulæ of known Celtic type.