The belief prevails in the minds of some that the Mississippi river is incompetent to transport pebbles of large size. The basis for this belief is the fact that the river seems to be carrying only relatively very fine material into the Gulf of Mexico. Therefore it seems that it is incompetent to transport material of cobble or gravel or even coarse sand grades in its lower course. Relatively coarse cobbles are transported along the river's bed at least as far south as Cairo, Illinois.
Proceedings of the Iowa Academy of Science
©1927 Iowa Academy of Science, Inc.
Lugn, A. L.
"Discussion of a Sample of Cobble Gravel from the Mississippi River,"
Proceedings of the Iowa Academy of Science, 34(1), 253-256.
Available at: https://scholarworks.uni.edu/pias/vol34/iss1/64