"The early inhabitants of the region under notice were wonderfully skilful in turning the result of the natural weathering of the rocks to account. To construct a cave-dwelling, the entrance to the cave or the front of the open gallery was walled up with adobes, leaving only a small opening serving for both door and window. The cliff houses take the form and dimensions of the platform or ledge from which they rise. The masonry is well laid, and it is wonderful with what skill the walls are joined to the cliff, and with what care the aspect of the neighbouring rocks has been imitated in the external architecture." [Footnote: Nadaillac, "Prehistoric America," Lond. 1885, p. 205.] In Asia also these rock-dwellings abound. The limestone cliffs of Palestine are riddled with them. They are found also in Armenia and in Afghanistan. At Bamian, in the latter, "the rocks are perforated in every direction. A whole people could put up in the 'Twelve Thousand Galleries' which occupy the slopes of the valley for a distance of eight miles. Isolated bluffs are pierced with so many chambers that they look like honeycombs." [Footnote: Reclus, "Asia," iii. p. 245.] That Troglodytes have inhabited rocks in Africa has been known since the time of Pliny. But it has hardly been realised to what an extent similar cliff dwellings have existed and do still exist in Europe. In 1894, in my book, "The Deserts of Southern France," I drew attention to rock habitations in Dordogne and Lot, but I had to crush all my information on this subject into a single chapter. The subject, however, is too interesting and too greatly ramified to be thus compressed. It is one, moreover, that throws sidelights on manners and modes of life in the past that cannot fail to be of interest. The description given above of cliff dwellings in Oregon might be employed, without changing a word, for those in Europe. To the best of my knowledge, the theme of European Troglodytes has remained hitherto undealt with, though occasional mention has been made of those on the Loire. It has been taken for granted that cave-dwellers belonged to a remote past in civilised Europe; but they are only now being expelled in Nottinghamshire and Shropshire, by the interference of sanitary officers.