WATEH DEPOSITS 



List of Samples in Table 7. 



m 



56. Limestone gravel from Barton Creek, Austin, Texas, 



57. Limestone gravel from Barton Creek, Austin, Texas. 



58. Recent gravel in the bed of a creek, Linwood, Iowa. 



59. Sand from the bed of Hat Creek, South Dakota. 



60. Recent gravel in the bed of a creek near Linvrood, lov^^a. 



61. Sand from a creek north of Linwood, Iowa. ' 



62. Sand from the bed of Totogatic Once, Douglas County, Wisconsin. 



63. Sand from ripples forming under water in a creek, Buffalo, Iowa. 



64. Sand in the bed of a creek near Linwood Springs, Iowa. 



65. Sand from a creek, Linwood, Iowa. 



66. From a heap of sand laid down on an alluvial iiat by a creek during a 



flood, Linwood, Iowa. 



67. Sand deposited on the alluvial flat of a creek during a flood, Linwood, 



Iowa. 



68. Sand in a creek five miles north of Ardmore, South Dakota. 



69. Recent sand in a creek five miles north of Ardmore, South Dakota. 



List of Samples in Table 8 



70. Recent alluvium, Baltimore, Maryland. 



71. Recent silt from a creek five miles north of Ardmore, South Dakota. . 



72. Alluvium from a small stream, Baltimore, Maryland. 



73. Silt from Canton Hollow, Baltimore Harbor, Maryland. 



Drifted sediments in large streams. — In 27 samples of sediments of 

 the coarser kinds in large streams, it is evident that there are great dif- 

 ferences in sorting. More than 1 per cent to each grade occurs in only 

 three grades in the best sorted samples, while extreme imperfection of 

 sorting has resulted in the distribution of such quantities through nine 

 grades in one of these samples. On the average, more than 1 per cent 

 is found scattered through five and a half grades, and all measurable 

 ingredients are scattered in about six and a half grades. In less than 

 half of the samples the admixtures form two decreasing series on both 

 sides of a single maximum, for 14 samples show one secondary maxi- 

 mum, while two samples show two secondary maxima. In a general 

 average there is a slight excess of finer admixtures, but there is never- 

 theless a very slight minor maximum in the coarse admixtures five 

 grades distant from the principal maximum. In the average more than 

 1 per cent is found in eight grades, while appreciable quantities of less 

 than 1 per cent are found in three more grades of coarse admixtures and 

 in two additional grades of fine admixtures — that is, to say, quantities 

 exceeding 0.1 per cent are distributed through 13 grades. 



