134 KANSAS ACADEMY OF SCIENCE. 



months, or 300 days, it carries out 266,000,000 cubic feet, of which 155,000,000 are 

 brought down from Colorado, leaving 111,000,000 cubic feet to be taken from the State. 

 The Kaw carries out yearly 322,000,000, of which 135,000,000 comes from Colorado and 

 Nebraska, leaving 1S7, 000,000 as its work within the State. The other streams carry off 

 107,000,000 cubic feet in a year. The total amount carried off by all the rivers is 

 695,000,000 cubic feet, of which 405,000,000 are removed from the surface of the State 

 of Kansas each year. This is 15,000,000 cubic yards; truly an enormous amount, if it 

 were carted off by human agency. 



RATE OF DENUDATION: 



Enormous as this amount may seem, at this rate of denudation it would take 470 

 years to remove a single inch from the entire surface of the State, and 5,640 years to 

 remove one foot. Within the historic period of the era of man — say 6,000 years — the 

 amount of rock and soil removed from the surface of the land between the Missouri 

 river and the mountains, averages only one foot in depth. 



We can look back and see readily enough through the dim vista of 6,000 years, and 

 are quite able to see the same rivers, and the same rolling prairies ; the same north and 

 south winds; the same heavy rains of summer and dryness of winter; the same buffalo 

 grass, with its cropping herds of buffalo ; the same sparse cottonwoods and willows near 

 the streams ; the same limestone ledges in the western part of the State ; the same sand- 

 stones and fire-clay in the center ; the same traces of coal in the southeast. Some of the 

 flinty-capped hills of Greenwood, Saline and other counties may seem now a very little 

 taller than then, and an occasional sand-hill, south of the Arkansas, may be in a new 

 position, but in general, the topography and climate are very much the same ; except 

 that now the earth is drier, there is less water in the rivers, and denudation is less rapid 

 than then. 



Since the last glacial epoch, assuming that the height of the glacial period was when 

 the earth's perihelion occurred at or shortly after the summer solstice, say 11,342 years 

 ago, the amount of degradation has scarcely reached an average of two feet. Can there 

 be a more forcible argument presented to show that time is long? Truly, "the mills of 

 the gods grind slowly; yet they grind exceeding small." 



There has never been a time when our long, broad, tortuous valleys were filled to 

 the brim with the waters of a foaming, rushing, abiding river. If there are evidences 

 at the base of any cliff of its having been washed by water, it is because the little stream, 

 now somewhere near the middle of the valley, was once washing its base. Most small 

 rivers and streams, in the course of time, travel all over their valleys. For at every 

 bend a stream is constantly encroaching upon the further bank and building up the near 

 one. Constant change of this kind will cause a stream, in the course of time, to touch 

 every part of the valley bottom, even to washing the base of an occasional bluff. The 

 width that valleys now have has been attained by the slow process of weathering, at a 

 rate, perhaps, not to exceed one or two inches in a century. The alluvial soil that fills the 

 bottoms has been washed there from the uplands, and blown there by the winds, and 

 blackened by animal and vegetable humus and the products of prairie fires. 



But the evidences at hand show that a depth of 3,170 feet over the entire State has 

 been washed away. At the rate of our calculation, which, in past seons, at least, will not 

 probably hold good, this would require nearly 18,000,000 years to remove what has been 

 removed. This is equal to 840 great perihelional cycles or Platonic years ; 840 times 

 that this land has endured a warm, sometimes a subtropical climate ; 840 times that it 

 has undergone the rigors of a glacial period, or been nearly immersed in the sea since the 

 deposition of the pliocene tertiary. The mind stands appalled at the magnitude and mean- 

 ing of these figures. 



Was the rate of erosion, during the great Platonic winter in the Arctic regions, or 



