STEVENSO^\ COAL BASIX OF DECAZEVILLE, FRANCE 289 



and Loire are not the same as those probable in the region under consid- 

 eration. Those rivers rise in the highlands and flow for a long distance 

 through a plain country. Yet there are resemblances and the movements 

 of the Avater are much the same. The devastation produced by rain- 

 floods is not brought about by the moving water directly, but by the ma- 

 terial which is carried, and that is collected by the way. In any case, 

 the water does not come down as a high wave, but with the face rising 

 gradually up stream. I^o matter how rapid the rise of a rain-flood may 

 be, it is gradual, and only loose materials lying on the surface are gath- 

 ered up to be carried off. When deep, the water moves slowly below, 

 rapidly above. If the flood pass over a forested plain, its speed is checked 

 in flowing through spaces between the trees, and practically the only 

 injury done is by deposit of mineral material. Even when a flood passes 

 over meadow land bordering the stream the destrtiction is by burying the 

 soil, as every one knows who has observed the conditions on rivers subject 

 to floods. After a high flood on the Coimecticut river, the maize growing 

 on unprotected soil of the "bottoms" had not been washed away ; but the 

 rapidly moving water at six feet above the ground liad pushed against 

 the spreading tops and had overturned the plants, which lay spread on the 

 surface. The peat bogs existing in many places along the sides of the 

 river have been exposed to floods, great floods, for centuries, but they are 

 intact except along the border, where itnderctttting of the loose material 

 on which they rest has caused portions to fall into the stream and has 

 made the edge ragged. Kuntze has told the same story about the great 

 peat areas of the La Plata region. 



That the running water of floods is not the direct cause of destruction 

 is certain. Every one has observed little islands in streams subject to 

 floods, islands covered with trees, though in flood time these may be sub- 

 merged for a brief period to the depth of 10 feet or more. The streams 

 issuing from the eastern face of the Eocky Mountains are given to fre- 

 quent rise of 10 or more feet, the rise being very sitdden, yet many of 

 them have wooded islets, most inviting camping places for the inex- 

 perienced traveler. Above Vigeois, between Brive and Limoges, the 

 stream has been dammed. !N"ear the head of the pond, the writer saw in 

 1910 a young tree about eight feet high growing midway in the stream 

 in the cleft of a large rock fragment and only a few inches above the 

 level of the water. That tree had resisted the floods of at least five years, 

 and some of the floods in that torrent must be extremely violent. Unless 

 the stream be loaded with debris, it can do little damage to the flooded 

 area : it will not tear up peat bogs, it will not remove the humus, it will 

 do insignificant injury to a forest. 



