CHAPTER III. 



SOILS OF THE LOWER PENINSULA. 



By the nature and distribution of the drift material, which has 

 ahnost exckisive occupancy of the surface of the peninsula, the 

 quality of its soil is determined ; the localities where its character 

 is modified by the lower rock formations are of very limited ex- 

 tent, and deserve no particular consideration in this place. The 

 soil possesses two important requisites for vegetation. It gives to 

 the plant a secure hold in its position, and furnishes to the roots 

 the material necessary for life and growth. Soil is composed of 

 pulverulent particles of mineral substances, generally mixed with a 

 proportion of organic matter. The mineral components must 

 contain all the chemical elements which enter into the composition 

 of plants, in a condition available for absorption by the roots. In 

 moist conditions, it has a certain degree of coherence and plasticity ; 

 it is porous, readily absorbs water, and retains it with a certain 

 tenacity. These are the general requisites for a soil, to make it 

 adapted for the growth and nutrition of plants. 



The chemical elements necessary for the organism of vegetation 

 are oxygen, carbon, hydrogen, nitrogen, sulphur, phosphorus, 

 chlorine, iodine, potassium, sodium, calcium, magnesium, alumi- 

 nium, silicium, iron, manganese — all of which are to be found distrib- 

 uted in varying proportions almost everywhere on the surface of 

 the earth. 



Soil constantly forms by the action of atmospheric influences 

 on the superficial rock beds, slowly effecting their chemical 

 decomposition, or causing mechanical disintegration by frost or 

 mutual trituration. A soil forming on the spot by decay of the 

 underlying rock beds participates in their chemical composition, 

 and may be destitute of certain ingredients necessary for a good 

 soil. Soil formed of drift material, being composed of the greatest 



