FORESTS, RESERVOIRS, AND STREAM FLOW 273 
But 1879 was a low-water year in the Mississippi Basin and the quan- 
tity for average years may probably be 1500 million tons and for 
extreme years, 2000 million tons. 
Let us look these prodigious quantities squarely in the face and 
see what they mean. Where does this enormous volume of soil come 
from? Is it, as one might infer from published references to the 
subject, from our cultivated fields—an annual toll laid upon the pre- 
cious fertility of our agricultural lands? Not at all. Only a very 
small proportion comes from this source. Possibly half of the total 
quantity of sediment goes down by the Mississippi. All authorities 
agree that the greater portion of this comes from the Missouri. From 
computations which the writer has made, he believes that fully two- 
thirds of it comes from that source. The observations of 1879 indicate 
that five times as much sediment comes from that stream as from the 
Ohio. But where does the Missouri get it? Almost entirely from 
the most useless areas of land with which any country was ever 
afflicted. The barren Bad Lands are the principal source. Much 
comes from the mountains; much from the sand hills; very little, 
relatively, from cultivated areas. Of the remainder of the soil wash of 
the United States, by far the greater portion comes from other similar 
sections of the West where the streams carry enormous loads of sedi- 
ment. The entire Colorado system is even more distinguished in this 
respect than is the Missouri. The same is true of the Rio Grande, the 
Pecos, and the upper courses of the Arkansas and Red. Even the 
streams of the Great Interior Basin are heavy silt bearers, and the 
same is true of many of the streams of the Pacific Coast. The streams 
flowing into Puget Sound are heavily laden with silt at certain por- 
tions of the year, and the great Columbia Bar is impressive evidence 
of the vast burden of sediment which that mighty river has carried 
to the sea. Nearly all the annual load carried by these streams 
is entirely unaffected by anything which Man has done. It is the 
regular natural carving down of the hills and building up of the 
valleys and estuaries below. 
The Eastern streams are clear and sediment-free compared with 
those of the West; but even in these, a large portion of their sediment 
is eroded from the gorges and cafions of the hills and mountains, which 
will continue to wash away as long as the rivers flow. This particular 
class of erosion, on both Eastern and Western rivers, is far less objec- 
