ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 155 



■ 



from the plateau. This permits the growth of numerous 



herbs. Here and there small 



the face of the bluffs. 



small 



3 limestone where it borders the river. 



^^ xxxxx..^v^. numerous small terraces arc formed, 



the" limestone apparently being removed according to its 



stratification (plate 15, 2). 



on the Missouri side are not wide, 



nd a mile or more. Especially in 



bottoms 



summer thoy are subject to overflow and 



same 



American 



Lllal; tilt; vj\^>^iAjjc*iii-Kj ^x V — --J. rrn • 'x If 



Bottom elect to build their homes on stilts. The river itselt 

 derives its distinguishing features from the Missouri,* such 

 as turbid waters, shifting bars and channels, rapid 

 of alluvial banks and extensive accretions, building 

 removing islands, tow-heads and battures with great 



(plate 11). 



and 



Opposite St. Louis, in St. Clair and Madison counties 



most northern portion of the most 



Mississippi, known as the American 



Bottom (plate 11). Extending from the mouth 



miles above the mouth 



more 



the Missouri, it occupies a strip some 80 miles long wi 

 average width of 4 miles. It represents older as well as 

 recent river deposit. This, in our section, is m places 

 covered by the rich mud of the Missouri combined with a 

 large amount of vegetable matter brought down by the 

 Mississippi. Close to the river its level is but slightly elevated 

 above that of the latter ; farther inland its surface rises sev- 

 eral feet. Where the land is low and mainly consists of 

 clay it constitutes what is known as the "wet bottom " 

 other, higher places, where the soil is sandy and which largely 

 lack the recent river deposit, are designated as ''dry bot- 

 tom " The latter is met with on the west side of Horseshoe 

 Lake and in the vicinity of Cahokia. Here and there woods 



"T^son. Rep. U. S. Engineers. 2= : 472. 1875 See Tod^ J. E. 

 Formation of Quaternary Deposits. Missouri Geological Survey. 10 : 192. 



1896. 



