<504 STEVENSON— FORMATION OF COAL BEDS. [November 3, 



under water, while vegetation is encroaching from the sides. It is 

 quite possible that this explanation of the Lake Drummond condi- 

 tion is correct, but that lake is shallow, only 6 feet, and the trees are 

 erect ; in the deeper lac d'Etailleres. the trees were prostrated by 

 breaking of the mat. To illustrate the succession in such a case, he 

 gives the section of a bog in Denmark : 



Feet. Inches. 



1. Fibrous yellow peat with undccomposed mosses 3 8 



2. Oak layer, wood still sound, trunks 2 to 3 ft. diameter. 



3. Peat, yellowish 6 



4. Birches, prostrate, Bctuhi alba 3 o 



5. Black peat 4 o 



6. Pines, 6 to 10 inches diameter, most of them pointing 



toward center of the basin, retaining their branches, 

 embedded in a mass of leaves, cones, etc 8 o 



7. Black compact peat 4 o 



and the bottom not reached. This peat was mined for fuel, the 

 works being extensive. The general description by Lesquereux 

 shows that the conditions are not wholly the same in his localities as 

 in many areas within the United States. They suffice to show that 

 Spliag)iii}ii is a late arrival, though in Switzerland, as in some other 

 portions of Europe it is more important than in this country, where 

 sphagnum-peat rarely exceeds 3 feet. 



As illustrating this, one may cite Vogt's^^^ description of a 

 Hochmoor at the Fonts of the Canton Xeuenburg. This lies be- 

 tween two villages built on limestone benches on opposite sides of a 

 valley. In the middle ages, each village was visible from the other, 

 but that is no longer the case. The bog has raised itself, hill-like, 

 growing most rapidly along the middle line. This mass is ^^/'/za^rwwm 

 and its mode of growth shows well the ability of that moss to retain 

 water, so as to thrive at considerably above the water level. 



Heer"" says that life on land began with minute forms and few 

 types. So, in the water, alg?e begin the work. Even pure fresh- 



"° C. Vogt, " Lehrbuch der Geologie," 2te Aufl., Braunschweig, 1854, Vol. 

 XL, p. no. 



'" O. Hcer, " Die Schieferkohlen von Utznach und Diirnten," Zurich, 

 1858, pp. 1-4. 



202 



