48 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



Other marsh plants. On Loch Brown, the peat cover was com- 

 pleted over the site of a decayed forest in less than 50 years. In 

 1756, the Wood of Drumlanrig was blown down and experienced a 

 similar fate.*" 



Miller*^ has cited the Earl of Cromarty's description of peat 

 growth in central Ross-shire. When very young, the earl had ob- 

 served a wood of very ancient trees, doddered and mossgrown, evi- 

 dently passing through the last stages of decay. Many years later, 

 he passed through the same district and found that the wood had 

 disappeared, while the heathy hollow was occupied by a green 

 stagnant morass. In his old age, he revisited the locality ; the sur- 

 face was irregular and pitted, for the highlanders were digging 

 peat in a stratum several feet deep. The aged forest had been 

 replaced with an extensive peat moss. 



The sphagnum-stage is not rarely the first. Dachnowski*- found 

 Sphagnum growing in Ohio on wet sand, where it formed tussocks 

 often more than 4 feet high. This matter will be considered in 

 another connection. 



It may be well to note, parenthetically, some other observations 

 by Dachnowski. Davis had recognized in Michigan that Sphagnum 

 is indifferent to calcareous salts, growing as well where the water is 

 hard as where it is soft. In Ohio, the nature and quantity of the 

 mineral salts seem to be unimportant, since the heath-sphagnum 

 meadows are abundant in counties where they rest on limestone, 

 while in one locality Sphagnum grows in profusion near springs 

 charged with calcium carbonate ; this plant in Ohio as in Michigan is 

 indifferent to that salt, for Dachnowski found it abundant in one 

 locality and wanting at another, the conditions being the same in 

 both. Deficiency in mineral matter does not prevent growth of 

 trees on peat ; they grow well on the floating mat of heath-sphagnum 

 and in places where the peat is 30 feet thick. In Ohio, the heath- 

 association does not mark the final stage, for it is followed by the 

 bog shrubs. The final stage is marked by the bog-forest association, 



40 A. Geikie, " The Scenery of Scotland," 2d ed., London, 1887, pp. 388-392. 



41 H. Miller, " The Old Red Sandstone," Boston, i860, p. 174. 



42 A. Dachnowski, " Peat Deposits of Ohio," Geol. Surv. Ohio, Bull. 16, 

 1912, pp. 224-256. 



