A second class of Cornish antiquities comprises private buildings, whether castles or huts or caves. What are called castles in Cornwall are simple intrenchments, consisting of large and small stones piled up about ten or twelve feet high, and held together by their own weight, without any cement. There are everywhere traces of a ditch, then of a wall; sometimes, as at Chûn Castle, of another ditch and another wall; and there is generally some contrivance for protecting the principal entrance by walls overlapping the ditches. Near these castles barrows are found, and in several cases there are clear traces of a communication between them and some ancient Celtic villages and caves, which seem to have been placed under the protection of these primitive strongholds. Many of the cliffs in Cornwall are fortified towards the land by walls and ditches, thus cutting off these extreme promontories from communication with the land, as they are by nature inaccessible from the sea. Some antiquarians ascribed these castles to the Danes, the very last people, one would think, to shut themselves up in such hopeless retreats. Here, too, as in other cases, a popular etymology may have taken the place of an historical authority, and the Cornish word for castle being _Dinas_ as in _Castle-an-Dinas_, _Pendennis_, etc., the later Saxon-speaking population may have been reminded by _Dinas_ of the Danes, and on the strength of this vague similarity have ascribed to these pirates the erection of the Cornish castles. It is indeed difficult, with regard to these castles, to be positive as to the people by whom they were constructed. Tradition and history point to Romans and Saxons, as well as to Celts; nor is it at all unlikely that many of these half-natural, half-artificial strongholds, though originally planned by the Celtic inhabitants, were afterwards taken possession of and strengthened by Romans or Saxons. But no such doubts are allowed with regard to Cornish huts, of which some striking remains have been preserved in Cornwall and other parts of England, particularly in those which, to the very last, remained the true home of the Celtic inhabitants of Britain. The houses and huts of the Romans were rectangular, nor is there any evidence to show that the Saxon ever approved of the circular style in domestic architecture.