112 
IOWA ACADEMY OF SCIENCE Vot. XXVII, 1920 
Fig. 16. Bluffs along west shore of Mississippi river. Abounds in asters and 
goldenrods. West slope. 
pounds of calcium and magnesium. All of these elements are 
essential for plant foods. It is generally recognized that the 
flora of limestone and sandstone regions differ, but this region in 
which both limestone and sandstone occur abundantly, shows a 
richer flora with reference to number of species of plants than is 
generally seen in a region in which either sandstone or limestone 
is the dominant constituent. 
While the west side of the river bears a luxuriant mesophytic 
forest, (Fig. 16) with only an occasional dry ridge or exposed 
peak bearing the prairie verdure, the weathered and exposed 
Wisconsin shore of the river in this vicinity bears a sparse and 
Fig. 17. Weathered aspect of Wisconsin shore near Prairie du Chien. Fast slope. 
Silky aster, Fragrant Goldenrod and Blazing Star. 
