I9I1.] STEVENSON— FORMATION OF COAL BEDS. 571 



Javan and Sumatran forests, where hard woods grow, fallen trees, 

 many decades old, lie in great numbers and are still in good condi- 

 tion for export. Termites and fungi are effective agents for de- 

 struction of wood in the tropics, but the moisture is almost equally 

 effective in preventing the decay. During the Sumatra expedition, 

 Koordes saw a great, always green Flachmoor, with a 30-meters 

 high mixed forest, extending along the Kampar river at more than 

 90 kilometers from the coast. As Koordes had made no close study, 

 definitive evidence was wanting to prove that this moor had a true 

 peat floor. But Larive made the necessary sounding at Potonie's 

 reouest and discovered that the peat in this tropical moor is 9 meters 

 thick. 



Examination with the microscope proved the presence of pheno- 

 gams ; spores or pollen ; occasional brown threads belonging possibly 

 to fungi ; some resin-like bodies, etc. The high content of silica in 

 the ash explains absence of diatoms in the microscopic preparations. 

 Chemically, the material is a true peat and German experts pro- 

 nounced it a good fuel. The ash in the dry material is 6.39 per cent, 

 while good north German Flachmoor peat has 5 to 7 per cent. The 

 ash of the Sumatran peat contains 74 per cent, of silica. 



Koordes estimated the area of the freshwater swamp on the left 

 bank of the Kampar at 80,000 hectares. At both camps within this 

 swamp, the water was stagnant, dark brown and slightly astringent. 

 Walking over the swamp was possible only because roots of trees 

 covered the surface with a dense network. The character of the 

 growth, as shown in Fig. 52 of Potonie's work, is a clear instance 

 of adaptation such as is seen in the Taxodium of the southern United 

 States ; for the roots are widespread horizontally just below the 

 surface, uniting into " broom-shaped air roots " and " asparagus- 

 shaped pneumatophores." The trees of the forest are mostly ever- 

 greens, 25 to 30 meters high and closely set. The underbrush con- 

 sists, for the most part, of the same species but its growth is slow, 

 owing to the dense shade. The forms are all dicotyledonous and the 

 flora is wholly of inland type. Grasses, sedges and mosses are prac- 

 tically wanting; it is a forest moor. The stagnant pools, poor in 



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