246 ANNUAL REPORT STATE GEOLOGIST. 



through. For example, while the bottom lands are here largely 

 under cultivation, in other parts of the state large areas of such 

 exceedingly fertile soil lie uncleared. The predominance of 

 sandy soil in the uplands, and the presence on the tops of the 

 hills of black jack timber is merely local. 



The effect of soil on the distribution of plants. — A portion 

 of the writer's work in Independence county was to trace the 

 parting between a stratum of sandstone and an underlying 

 stratum of limestone. From the first it was noticed that the 

 vegetation borne on the two soils formed from these rocks 

 varied in general aspect, but when it came to stating the precise 

 items of difference some difficulty was experienced, for lists of 

 the plants seen on each of the soils were nearly identical. 

 After a short time, however, the difference began to be per- 

 ceptible. It lies in the preponderance of certain species, a 

 very few possibly being limited to one of the soils. The dif- 

 ference is most strikingly seen upon hillsides, the bases of 

 which are of limestone, the summits of sandstone. On the 

 former soil the most abundant trees are the redbud {Cercis 

 canadensis), the chestnut oak {Quercns prinoides), the black 

 walnut and the shell-bark hickory {Carya alba). Rarely was 

 any one of the first three of these found in the sandy soil 

 above. The last mentioned is abundant in both situations. 

 The sugar maple {Acer saccharinum) was sometimes found on 

 the limestone, but never on the sandstone. The same is true 

 of a skullcap [Scuttellaria versicolor) and the harebell {Cam- 

 panula americana). The other trees, which constitute the 

 great majority of species, are scattered about equally over 

 both soils. The height of the limestone above the bottoms of 

 the valleys varies from two to three hundred feet down to 

 nothing, while the change in vegetation is abrupt and coin- 

 cides invariably with the change in soil, so that the climatic 

 differences between the top and bottom of the hills are not 

 the cause of a difference in vegetation. The depth of soil, too, 

 appears to be about the same in both cases. 



