Geyser basins lower the country around them and leave hills in relief. The proportions of basins and hills depend upon the runoff of rotting and dissolving rock. The shape of a hill standing high, what Davis called a monadnock in New England, depends on its whole history, not on its hardness. Ascutney Mountain stands high as a lump because surrounding slates have rotted down. Mount Monadnock may stand high because the springs under the river pattern of cracks neglected it in the rotting and crunching of a continent. Dynamic weight eternally falling makes low places. Hardness against weathering makes a mountain high only as a relic or residual. It is a node in the gigantic process of gravitation rotting and the spring squirting of groundwater. The water heats, rises, dissolves, siphons, springs up, and transports dirt. Underneath is a definitely heated earth crust. Accordance of summit levels of mountains and hills as one looks across country does not have to represent an upraised plane surface. There is more undermining where the spring squirting is most voluminous. When spring squirting is equal, the opposed slopes of a valley adjust themselves. The tree line, the snow line, the rain line, and the wind line are definite levels of erosion. Under it all the rotting rock is falling toward the earth’s center, slowly, creakingly. The everlasting hills are not everlasting, they are everfalling; rocks, boulders, slopes, waters, gravels, sands, and muds. And adjustment to the atmosphere and groundwater surface is irresistible. [Illustration: _1. Experimental Geology Laboratory, Harvard University, 1900_] [Illustration: _2. Fountain at edge of lava lake, May 17, 1917_] The notion of erosion pulling down hills to a flat plane near sea level is fascinating to geometry-minded people, but not to the mechanically minded. A flat plane near sea level in the Mississippi delta is where the river has swung right and left against valley walls, over its own flood plain. A flat plain, secured by ice sheets or planed off by encroaching wave action as land sinks is mechanically probable. In these circumstances we look for river or ice or wave-beach deposits. But an “almost plane” occasioned by the multiple action called erosion down to base level is to me the delightful dream of map students. If a landscape has been planed off, a machine router or planer did it. The great rivers of China have had a long time to bang back and forth against their confining boxes of rock and on top of their own mud.