As the radial cracks in the drawing by Suess if extended meet in the Lipari Islands, so also several canals on Mars run together in a so-called lake (Lowell called them “groves” or “oases”) which evidently is a centre of collapse (many appear on Fig. 17). It is plain that all crossings of the “canals” are not necessarily such centres of collapse. (See maps Figs. 17 and 17a at end of book). We shall consequently assume that the canals on Mars correspond to the geological dislocation fissures on the Earth. Along these fissures emerge the gases liberated in the cooling process on both planets; which are similar gases to those which escape through the volcanoes. These vapours are primarily water, next carbon dioxide and, in considerably smaller quantities, sulphuretted gases and hydrochloric acid. They discharge through cracks in regions which, geologically speaking, not so long ago were the scene of volcanic activity. In the dislocation-grooves, lakes, and water courses are often formed, as we may observe in several places in Sweden, for instance near Stockholm. Assume now a gradual cooling of our earth. Most territories are covered by stratified, comparatively light rocks. To the dislocation fissures water gathers from the surrounding strata and occasionally from the interior, partly washes away the loose material and transforms the fissures into furrows, generally with flat bottoms. Dissolved salts are carried to the sea. As cooling proceeds, the ocean commences to freeze. Each summer the surface melts to a certain extent, as is the case now in our polar regions. Finally, the entire ocean freezes to the bottom, the ice is now to be considered as a kind of rock, flexures and dislocations cease and the ice assumes a smooth surface. In the strong sunlight during the summer this surface thaws, as do the water-courses on the mainland, and these continue to carry their salts to the open surface water. At the approach of winter the latter solidifies again but not as the water in our inland lakes from the top but from the bottom, as ordinary sea-water possesses its greatest density below the freezing point while the opposite is true of fresh water. The consequence is that the ice foundation grows upward and as the surface water becomes increasingly shallow it is turned into a concentrated salt solution. With a further drop in temperature the ice formation is accompanied by crystallization of the salts.