LYSICHITON CAMTSCHATCENSE (l.) SCHOTT 
205 
large stool in situ and the remains of GauUheria shallon bear witness 
of this relatively dry stage. The replacement of the forest by the 
Sphagnum denotes the critical stage in the history of the bog. The 
exact cause of the destruction of the forest is very difficult to conjecture. 
Changes in the level of the ground water is a reasonably safe assump- 
tion. Some of the current opinions on this topic will be discussed 
below. For our interpretation of the past history of Lysichiton in 
Fig. 5. 
A. 60 cm. of Sphagnum teres peat containing leaves and root systems of the present 
flora, notably of Ledum, Kalmia and Oxycoccus. 
B. 15 cm. of brownish black mud. 
C. 20 cm, of Sphagnum palustre peat containing an abundance of leaves and twigs 
of Oxycoccus, rarer leaves of Tsuga heterophylla, Kalmia glauca, grasses, and 
twigs of Thuja plicata. 
D. 90 cm. of forest peat consisting of wood detritus and bark mixed with leaves, 
twigs and cones of Thuja plicata, leaves and twigs of Tsuga heterophylla, leaves 
of Ledum groenlandicum, Kalmia glauca, GauUheria shallon, grasses, seedwings 
of Pinus monticola, and whole plants of Camptothecium sylvaticum. Coal was 
occasionally met with. One large stool in situ was found. 
E. 150 cm. of Carex peat highly mouldered below with leaves of Kalmia and Ledum, 
and an abundance of Hypnum giganteum, and sparse Sphagnum. 
F. Clay. 
G. Moss peat. 
