THE INFLUENCE OF SOILS G7 



channels. Livingston thinks the character of the soil 

 made no difference here. All the heavy clay soil in 

 the southern townships^ whether rolling moraine or 

 till plain, he finds to have been occupied by the beech- 

 maple society (society 1). The oak-hickory society 

 was usually found on the light loamy soil, with transi- 

 tion zones between it and the beech-maple society 

 held by the maple-elm-agrimony society (No. 2). 

 The very sandy loam bordering the valley of the 

 Thornapple River was found to be occupied by the 

 oak-hazel and the oak-pine-sassafras societies.^ The 

 Grand Eapids sand plain was mainly covered with 

 societies 4 and 5. Hemlock was found in the north- 

 western section of the county in the beech-maple 

 society. "White pine existed in the northern portion 

 of the county. There were instances where white 

 pine grew in the beech-maple group. The inter- 

 mediate society 3 was found on the loamy soils and 

 on the dryer clay areas. On the lowlands plant so- 

 cieties are differentiated with reference to their posi- 

 tion in, or adjacent to, lakes, swamps, marshes, 

 springs and streams ; and the conclusion is reached 

 that the degree and character of soil-moisture, rather 

 than the type of soil itself, determines the distribu- 

 tion of plant species in this region, and presumably 

 elsewhere. It is suggested also that the recent 

 geologic history of the district may have had its in- 

 fluence. Since, as already known, tlio conditions of 



' Rept. State Bd. Geol. Survey of Mich, for the year 1901 : 

 Lansing, 1902; p. 81. 



