172 Transactions of the Academy of Science of St. Louis 
he is indebted would far exceed the space which should be allot- 
ed for acknowledgements. Individual citations of the work of 
some of the more important investigations are made at appro- 
priate places. Special: thanks are due Dr. Lewis -F. Thomas who 
suggested a study of the terraces and gave much help. 
‘TERRACES 
General Statement 
The correlation of the remnants of the terraces along the 
Middle Mississippi River reveals the existence at earlier times 
of three distinct and extensive alluvial deposits or terraces in 
addition to several less important ones. The three larger ter- 
races are not coextensive, and the evidence indicates that they 
were not formed contemporaneously. By the judicious coordi- 
nation of the evidence of the terraces with that of the drift it 
has been possible to reconstruct some of the salient events which 
occurred in the Middle Mississippi River Region during the 
Pleistocene. 
One of these terraces has a surface slope essentially parallel 
to the gradient of the Mississippi. This is the most extensive 
of the three terraces and has the lowest elevation, at least in 
this region. It is named in this report the Festus Terrace. 
Another of these terraces has a surface that is essentially 
horizontal. This terrace has a very broad extent, north, but 
not south, of St. Louis, It is always higher than the Festus 
Terrace within the limits of the region studied. It is called the 
Cuivre Terrace. 
The third of the extensive terraces has been greatly eroded, 
but the evidence points to the conclusion that its initial surface 
was essentially horizontal. This terrace is found only along the 
Missouri River, where it is always higher than the Cuivre 
Terrace. It is named the Boeuf Terrace. 
