MICHIGAN ACADEMY OF SCIENCE. 53 



of saturation, the thickness of the saturated layer, the steepness of the 

 slope, etc. The problem here involved -would appear to be one that 

 would repay an attempt at mathematical solution based on the known 

 laws of flow of viscous bodies. That a differentiation of the mass into 

 alternate bands of relatively more and less fluid materials, and that the 

 width of these bands determines the width of the visible stripes seems 

 almost certain. 

 University of Michigan, March 10, 1910. 



A WASTE FILLED VALLEY. 



A. E. PARKINS. 



(Abstract.) 



From an examination of ten or twelve valleys of intermittent streams 

 along the Huron River between Ypsilanti and Dexter, the writer found 

 that invariably Avhere these valleys headed in cultivated fields, the 

 valleys are waste filled and have flat floors. This would lead one to 

 suspect that such filling was produced by an increase in supply of ma- 

 terial from the head waters, due to the cutting away of the forests. 



The accompanying picture is an example of one of the best of such 

 valleys. That filling has taken place is evident from the following lines 

 of evidence: 



(1) The flatness of the floor, which in a valley of such great slope 

 should be V-shaped; 



(2) The sharp angle that the sides make with the valley bottom; 



(3) The partial burying of the trees; 



(4) The interesting features shown by the stump and the 5 ft. cliff 

 to the right. Just above the upper parts of the root of the stump is 

 a line of muck, and marks the position of the valley bottom before 

 filling. The deposits above this layer of muck are 31/2 ft. thick. By 

 a count of the rings on the stump, the tree when cut was 75 years old. 

 Prilling has taken place some time since the tree was a sapling gTow- 

 ing in the valley bottom. 



Another characteristic of all such valleys is the great number of 

 steps, caused by stones and twigs damming the channel at various 

 points, and, also, perhaps by the recession of the steps. 



In such streams the post-glacial cycle of erosion has been interrupted 

 by an increase in supply of waste from the headwaters. These valleys 

 may serve then as local examples of what took place during the close 

 of the Glacial Period in all valleys of south flowing rivers. 



M. S. N. C, April, 1910. 



