26 PROCEEDINGS OF THE INDIANAPOLIS MEETING. 



Great Plains of North America, where the slope is considerable and the beds soft, one 

 might suppose that the rivers would have already spread a network of tributary 

 ravines over the whole surface, notwithstanding its recent emergence. If they have 

 not done so it must be on account of some peculiarity in the form of the surface which 

 has resisted their approaches; and it will appear in the sequel that such is really the 

 case. 



The rivers of the Plains are hard at work scoring down the great sheets of sediment 

 over which they flow.. In no other part of the world are the waters so burdened with 

 silt. Given unlimited time for these rivers to cut away at the face of mother Earth 

 and they will reduce her featuree to the precise topographic type which prevails in 

 countries geologically old, where the rivers have been long at work. Every part of 

 the surface will be brought under the chisel of that untiring sculptor, flowing water, 

 and consequently ever}' part of the surface will become a part of the valley of some 

 river. Each little depression will lead out to a larger one, that into another still 

 larger, and so on to the great trunk lines of continental drainage, and ffinally to the 

 ocean. Wherever the rain may happen to fall it will find an open path to the ocean — 

 a path for the rain made by the rain. That is the fundamental type of water sculpture. 



Not only will the rivers take possession of the whole surface, but they will cut it 

 all down to base level. Towards the accomplishment of this enormous labor they 

 have just made a beginning — in some places not even a beginning. Their ultimate 

 task is to cut down the whole surface to base level, but they have not yet taken pos- 

 session of the whole surface. Great stretches of table-lands are yet independent of 

 their dominion. In regions of erosion the water-shed is a line. On this side the rain- 

 drop falling may run off" to the Atlantic ; on that side its twin drop falling may run 

 oflT to the Pacific. On the plains the water parting, instead of being a line, bulges 

 out here and there into a broad band. It splits into two lines and loops around a 

 space which does not belong to the valley on either side. Here falls a drop which 

 runs ofi'to the south ; yonder, a score of miles away, falls a drop which runs off" to the 

 north. Between lies a broad table-land, where the rain may sink into the earth, and 

 by subterranean ways ultimately get into some river, or it may be evaporated and 

 return to the heavens; but the one thing which rain persistently does everywhere 

 else — that is to say, run along the surface in ravine, creek, river, to the ocean at 

 length — that one thing it persistently refuses to do on these table-lands. 



Some notion of the peculiarities of surface which cause this unusual behavior of the 

 water may be obtained from the stereogram presented herewith, illustrating a portion 

 of the surface in the western part of Custer county, Nebraska. A sort of regular or 

 persistent irregularity is apparent. In contrast with the ordinary landscape there is 

 a striking absence of leading lines. There are valleys, but they lead nowhere ; there 

 are basins, but they have no outlet; there are ridges and hills, but they have no con- 

 tinuity and no definite arrangement. Every depression soon bumps up against a hill ; 

 every hill slopes off into a hole. 



The general level is well maintained over a considerable area. The higher points 

 are so equal, so numerous and so close together that they form a level sky-line when 

 viewed from a little distance; but from these summits down to the bottoms of the 

 " lagoons " may be fifty or seventy -five feet. The roads, following section lines, cross 

 hills and valleys in endless succession. In other regions one may make the distinc- 

 tion of traveling "across the country " or not, according as he follows the valleys or 

 takes them transversely. Here there is no choice; it is "across the country," no 

 matter what direction is taken. 



