6^6 J. A. UDDEN — COMPOSITION 01^ CLASTIC SEDIMENTS 



List of Samples in Table 9 



74. Gravel from the bank of the Mississippi River, Davenport, Iowa. The 



sample contains many limestone pebbles of local origin. 



75. Holy Cross Mission, 200 miles above mouth of Yukon River, Alaska. 



76. Selkirk, Yukon River, Alaska, 200 miles above Klondike. 



77. Tanana Station, Yukon River, Alaska. 



78. Selkirk, Yukon River, Alaska. 



79. Dimraven, Klondike River, Alaska. 



80. Gravel from the bank of the Mississippi River, Davenport, Iowa. The 



sample contains much limestone of local origin. 



81. River bank gravel, Davenport, Iowa. The sample contains much lime- 



stone, as above. 



82. Sand from the north bank of the Mississippi River, New Boston, Illinois. 



83. Sand from the bottom of the Mississippi River, Rock Island, Illinois. 



84. From the bottom of the Mississippi River, near an island, southeast from 



Buffalo, Iowa. The bottom was perhaps being eroded. 



85. Beach sand thrown up by boat waves, Buffalo, Iowa. 



86. Recent river sand from the Mississippi River near the north bank of the 



Government Island, Rock Island, Illinois. 



87. From the bottom of the Mississippi River, Buffalo, Iowa. 



88. From the bottom of the Mississippi River during a flood, Buffalo, Iowa. 



89. Rampart, Yukon River, Alaska. 



90. Beach sand. Rock Island Harbor, Rock Island, Illinois. 



91. Sand from the forming beach in the Mississippi River, Davenport, Iowa.' 



92. Sand from the beach of an island in the Mississippi River, Buffalo, Iowa. 



93. Skagua, Alaska. In river coming down in bay, 1^^ miles from bay. 



94. Recent alluvial sand, Mississippi River bank, Davenport, Iowa. 



95. Sand bank on an island in the Mississippi River, Buffalo, Iowa. 



96. Beach sand from the Mississippi River, Rock Island, Illinois. 



. 97. Sand from the north bank of the Mississippi River, New Boston, Illinois. 



98, Gravel from the bank of the Mississippi River, Davenport, Iowa, The 



sample contains much limestone of local origin. 



99. Sand from the beach of the Mississippi River, Buffalo, Iowa. 

 100. Alluvium from the bottom lands east of Davenport, Iowa. 



Silt from large streams. — Only four silts from large streams have 

 been analyzed, and these are all from the Mississippi, in Illinois and in 

 Iowa. Such deposits are among the most common in all parts of the 

 world and it would be desirable to have more samples. They represent 

 deposits formed during floods. Taken in connection with similar de- 

 posits from smaller streams, they may be considered as indicating a con- 

 siderable uniformity in the sorting of the mechanical ingredients in 

 such sediments. Most samples have secondary maxima in the coarse 

 admixtures, or at least show a retardation in the decrease of quantities 

 in that direction, four or five grades distant from the maximum. 



