1905] TRANSEAUBOGS OF THE HURON RIVER VALLEY 425 



B. CHEMICAL FACTORS. i. Ground water. The ground water 

 of the Huron basin derives its mineral constituents from the glacial 

 drift. The following analyses show the character of the solution. 

 Quantities are expressed in parts per million (31). 



It is to be noted that they are all high in calcium and magnesium 

 content, and under favorable drainage conditions contain sufficient 

 minerals for plant growth. The ground water is of especial impor- 

 tance in the early stages of bog development, when the sedge and 

 aquatic vegetation is dominant. With the further development of 

 the sedge zone and the formation of a thick peat deposit, its relation 

 to the vegetation becomes of less moment. There is a notable 

 difference between the total mineral content of bog water and that 

 of the soil waters .adjoining. In the above table the total mineral 

 content of the ground water varies from 267.7 to 585 parts per 

 million. In three analyses of the bog water at the First Sister Lake 

 I found the total mineral content to vary from 89.9 to 219 parts per 

 million, the highest figure being that for the sample obtained near the 

 margin of the tamaracks, i. e., nearest the mineral soil. 



The absence of sphagnum from certain bogs has been explained 

 by the presence of calcium salts (15, p. 23, 1 6). In order to test 

 this point, I have cultivated the species found in this vicinity in tap 

 water and in a saturated solution of CaCO 3 , and have found no 

 detrimental effects due to calcium. The experiments will be dis- 

 cussed later. I further found that the ash of sphagnum growing at 

 First Sister Lake contained 18 per cent, of CaO. It would seem, 

 therefore, that, in so far as this vicinity is concerned, the presence of 

 calcareous waters will not explain the absence of species of sphagnum. 



