18 IOWA STUDIES IN NATURAL HISTORY 



Wabash rivers on the New Haven, Ills, sheet, and Nemaha 

 river on the Falls City, Nebr. sheet, all of which are streams 

 with meanders formed in old age, shows that these three 

 characteristics of meanders are more imaginary than real. 

 Few if any distinguishable differences between the mean- 

 ders of old age and crooks made in other ways are brought 

 out by the comparison of the meandering streams referred 

 to with typical crooked streams not in old age, such as Red 

 and Buffalo rivers on the Fargo, N. D. sheet. Otter creek 

 on the Brandon, Vt. sheet, Deerfield river on the Wilming- 

 ton, Vt. sheet, Des Moines river on the Boone, Iowa sheet, 

 San Joaquin river on the Westley, Cal. sheet, Tuolumne 

 river on the Westport, Cal. sheet, Canadian river on the 

 Brilliant, N. M. sheet, Stanislaus river on the Ripon, Cal. 

 sheet. There being no distinguishable differences between 

 the meandering streams referred to above and ordinary 

 streams which have never reached old age, it follows that 

 it is impossible to tell from the maps, after a study of the 

 curves themselves, whether intrenched meanders of the 

 second cycle of erosion or ordinary crooks of the first cycle 

 are illustrated in the Brazos river on the Palo Pinto, Texas 

 sheet, Monongahela river on the Brownsville, Pa. sheet, 

 Canondoquinet creek on the Harrisburg, Pa. sheet, Grant 

 and Platte rivers on the Lancaster, Wis. sheet, and Osage 

 river on the Tuscumbia and Forsyth, Mo. (Fig. 5) sheets. 

 Intrenched meanders might, however, in some cases at 

 least, be distinguished from consequent crooks by the pres- 

 ence of outer valley walls. If the meander belt is located 

 within outer valley walls and the stream is intrenched, the 

 curves would seem to have been inherited from the mean- 

 ders of an old age stage of valley development in a pre- 

 vious cycle. With this exception, which would rarely apply 

 except in the early stages of a second cycle following a 

 cycle which was interrupted before the valley walls became 

 indistinct, intrenched meanders as evidence of more than 

 one cycle in the erosional history of a surface would seem 

 to have little if any value. Only in combination with other 

 and more decisive evidences would they rise in other cases 

 above the rank of mere suggestion. 



