136 SCIENCE IN SHOUT CHArTERS. 



ble shelter from tlieir ravages. In spite of tins they do not al- 

 ways escape. In the October previous to my last visit a boat- 

 house and boat were swept away ; and one of the most recent 

 among the tracks that I saw reached within twenty yards of 

 some farm-buildings. 



What has become of the millions of trees that are thus 

 falling, and have fallen, into the Norwegian fiords during the 

 whole of the present geological era ? In considering this 

 question we must remember that the mountain slopes forming 

 the banks of these fiords continue downward under the waters 

 of the fiords which reach to depths that in some parts are to 

 be counted in thousands of feet. 



It is evident that the loose stony and earthy matter that 

 accompanies the trees will speedily sink to the bottom and rest 

 at the foot of the slope somewhat like an ordinary sub-aerial 

 talus, but not so the trees. The impetus of their fall must 

 launch them afloat and impel them toward the middle of the 

 estuary, where they will be spread about and continue floating, 

 until by saturation they become dense enough to sink. They 

 will thus be pretty evenly distributed over the bottom. At the 

 middle part of the estuary they will form an almost purely 

 vegetable deposit, mingled only with the very small portion of 

 mineral matter that is held in suspension in the apparently clear 

 water. This mineral matter must be distributed among the 

 vegetable matter in the form of impalpable particles having a 

 chemical composition similar to that of the rocks around. 

 Near the shores a compound deposit must be formed consisting 

 of trees and fragments of leaves, twigs, and other vegetable 

 matter mixed with larger propoitions of the mineral debris. 



If we look a little further at what is taking place in the 

 fiords of Norway we shall see how this vegetable deposit will 

 ultimately become succeeded by an overlying mineral deposit 

 which must ultimately conrtitute a stratified rock. 



All these fiords branch up into inland valleys down which 

 pours a brawling torrent or a river of some magnitude. These 

 are more or less turbid with glacier mud or other detritus, and 

 great deposits of this material have already accumulated in 

 such quantity as to constitute characteristic modern geologi- 

 cal formations bearing the specific Norsk name of oren, as 

 Laerdahoren, Sundalsoren, etc., describing the small delta 

 plains at the mouth of the river where it enters the termination 

 of the fiord, and which, from their exceptional fertility, con- 

 stitute small agricultural settlements bearing these names, 



