But though this house is so cleverly built, and is warm, and proof against everything but mild weather, the Innuit, if he can, will build a permanent winter house of drift wood, stones, earth, and sod and whale-ribs. These from the outside look like mounds of earth, and as soon as warm weather comes are nothing but wet cellars, which the inhabitants quickly abandon for the time, erecting with their walrus and seal skins a summer tent, called a _tupek_ or _topek_. The Point Barrow tupek is something like a tipi, without a smoke hole, as the fire is built outside when they can secure wood to build one. All the Alaska Innuit now use canvas tents of the “wall” pattern, when they can procure them. The Amerind of the interior of the northland, where timber grows, utilises it and the skins of the animals he kills. The Nenenot about Hudson Bay occupy, all the year round, a tent almost identical with the Dakota tipi. [Illustration: AN ALASKA ESKIMO WINTER HOUSE, POINT BARROW Interior and sections p. 221 ] No construction on the continent shows more skill than the Innuit snow iglu. The winter houses, of snow or other material, are usually occupied by two or more families. Many interiors of snow houses are lined with the summer tent covering to prevent the drip of the walls from falling on the occupants. [Illustration: INTERIOR GROUND PLAN OF A MOKI HOUSE] As the polar regions developed the snow-house; forest regions, bark and mat houses; barren plains, portable tents; so arid regions, where disintegrating cliffs furnished an abundance of flat slabs of stone, evolved stone houses, and broad dry valleys or plains lacking cliffs, timber, or large game, but yielding good clay soil, produced houses of mud or adobe; or, according to conditions, such combinations of these materials as were easiest and most practicable. It is next in order to review the houses of the arid regions constructed of stone, adobe, jacal, cajon, pisé,[195] etc., and the cavate lodges. To do full justice to the subject of houses would require a separate volume, but enough may be given here to present a general view. The occupied villages of the South-western United States are similar to the ruins found throughout that region, and the cliff-dwellings, which some writers would clothe with mystery, as has been mentioned, were no more mysterious than the occupied dwellings of the Moki; or any other Pueblo village, which, fortunately, remains inhabited by the builders.[196] The cliff-dwellings were constructed in cliffs simply because it was expedient to build them there and not because the builders were a race apart from other Amerinds. The canyons where the cliff-dwellings occur have bottom lands that are fertile and easily irrigated, both by stream water, and after the Pueblo fashion, by guiding shower waters with hoes amongst the corn. This in itself was a sufficient object for building in the canyons, and the huge, natural conchoidal alcoves that occur