Sixteenth annual meeting. 131 



and disintegrated rock washed entirely away and carried to the ocean, or more properly, 

 perhaps, the Gulf of Mexico. Asa matter of fact, it was much more than that; for, 

 where evidences of non-conformability appear between strata, it shows that there the 

 surface at one time underwent a period of denudation and subsequent subsidence and 

 immersion and consequent accumulation by deposition. 



But, not counting what we do not see, what must have been the length of time re- 

 quired to remove the 50,000 cubic miles we do see, and carry the material utterly away? 



Time is long. The existence of man is but a mere speck of time during this 

 measurable portion of eternity. 



SPECULATION. 



If we may judge of the past by the present, the time occupied in the removal of the 

 rock strata showing at the surface within the State of Kansas may be computed. No 

 part of the surface of the State comprises any portion of the igneous rocks formed dur- 

 ing the immeasurable past.* There are no outcropping rocks but those formed by sedi- 

 mentary deposition. 



Xo attempt, however, will be made in this paper to show the length of time elapsed 

 during deposition. Arguments will be confined strictly to the time elapsed during 

 degradation, whether continuous or interrupted. 



In this article no presumption is made at accuracy of statement. No necessity ex- 

 ists for it. Figures will be given only in general terms and approximately. When it 

 is remembered that an error in observation of even an inch in the depth of a river or 

 the thousandth part of an inch in the depth of sediment deposited in a vessel of water, 

 or of a week in the length of time a river should run during a year, might lead to an 

 error of a million years, more or less, it will be observed how utterly futile an attempt 

 at accuracy in these matters may be. 



DEGRADATION. 



The principal agents of degradation are water and air in motion. These will be 

 considered in turn : 



I. — The Agency of Water. 



The rivers of the State carry off constantly earth in two forms — in suspension and 

 in solution. Degradation by water, in Kansas, progresses mainly by two methods: 1st, 

 by denudation, or washing of the surface; 2d, by percolation, or seeping — drawing out 

 through springs, subterranean veins, etc. Both of these methods carry earth in the two 

 forms named. The first carries mud and light earths in suspension and organic sub- 

 stances in solution; the second carries mainly sand in suspension and various alkaline 

 salts and mineral matters in solution. The tendency or inclination, then, of surface 

 water is acid, of spring water is alkaline. 



The percentage of mud carried by a stream is greatest in a freshet; the percentage 

 of sand carried is nearly always the same in the same stream ; and the percentage of 

 mineral matters held in solution is always greatest in low water, and the amount nearly 

 always the same in a given river, whether the water is high or low. 



A third method of degradation, namely corrosion, or the wearing away of the bed of 

 a stream more rapidly than the surface of its basin, is still taking place to a small de- 

 gree in the headwaters of the Kaw tributaries; in the bed of the Kaw itself very little; 

 and in the Arkansas not at all. 



The upper tributaries of the Kaw receive their load of earthy matters mainly by 

 washing; the Kaw proper, Neosho and Osage partly by washing and partly by seeping; 

 the Arkansas almost entirely by seeping. 



The Arkansas bears evidence of being an older and maturer stream than the Kaw — 

 perhaps because its bed is filled every summer with water from the mountains; perhaps 



*Haworth, Sth Bien. Rep. Kan. Acad. Sci. 



