i88o.l 
The Formation of Coal. 
83 
soil on which they grew sunk down some hundreds of feet 
without disturbing them. This demands a great strain upon 
the scientific imagination, even in reference to the few cases 
where the trees stand perpendicular. As the majority slope 
considerably the difficulty is still greater. I shall piesently 
show how trees like those immersed m Aachensee may have 
become, and are now becoming, imbedded in rocks similar 
to those of the Coal Measures. 
In the course of subsequent excursions on the fjords of 
Norway I was reminded of the sub-aqueous forest of the 
Aachensee, not by again seeing such a deposit under water, 
for none of the fjords approach the singular transparency of 
this lake, but by a repetition on a far kr ger scale of t ie 
downward strips of denuded forest ground. Here in Nor- 
way, their magnitude justifies me in describing them as 
vegetable avalanches. They may be seen on the Sogne fjord 
and especially on those terminal branches of this grea 
estuary, of which the steep slopes are well wooded. But 
the most remarkable display that I have seen was in the 
course of the magnificent, and now easily made, journey up 
the Storfjord and its extension and branches, the Slyngstjord, 
Sunelvsfjord, Nordalsfjord, and Geirangerfjord. Here these 
avalanches of trees, with their accompaniment of fragments 
of rock, are of such frequent occurrence that sites ot the 
farmhouses are commonly selected with reference to possible 
shelter from their ravages. In spite of this they do not 
always escape. In the October previous to my last visit a 
boathouse and boat were swept away ; and one of the recent 
tracks that I saw reached within twenty yards of some farm 
bU \Vhathas become of the millions of trees that are thus 
falling and have fallen, into the Norwegian fjords during 
the whole of the present geological era ? In considering 
this question we must remember that the mountain s op 
forming the banks of these fjords continue downwards under 
the waters of the fjords which reach to depths that in some 
parts are to be counted in thousands of feet. , 
P It is evident that the loose stony and earthy matter that 
accompanies the trees will speedily sink to the bottom and 
rest at P the foot of the slope somewhat like an ordinary sub- 
aerial talus, but not so the trees. The impetus of then fall 
must launch them afloat and impel them towards the ^middle 
of the estuary, where they will be spread about and con- 
tinue floating, until by saturation they become dense enough 
to sink. They will thus be pretty evenly distributed ovei 
£e bottom. At the middle part of the estuary they will 
