3G8 EHRENFELD— JOINTING AS A FUNDAMENTAL FACTOR 



struction. Thus, Supan^^ says that " There can be no reason to 

 doubt that fjords are submerged valleys," and compares the Laxe 

 Fjord of Norway to the one which would be formed by the submer- 

 gence of the wedge-shaped Thalbucht of Salzburg, supposing that 

 the sea were to overflow it. This may be perfectly true as far as it 

 goes, but it leaves yet unexplained the reason for the similarity of 

 the structure of the two places indicated and also fails to explain 

 one of the characteristics of fjord coasts and that is their remark- 

 able parallelism of structure, a parallelism which unites their struc- 

 ture wnth the parallelisms seen in other aspects of the surface of 

 the lithosphere. The fracture or splitting theory is attributed by 

 Giinther to Peschel and Leipoldt and may be stated as follows : The 

 destruction and breaking up of the coast was attended with its ascen- 

 sion ; originally the cracking or splitting was not farther than the 

 ascent of the greater layers which, in consequence of the uplift, 

 arched over and later the fracturing extended through a shrinkage 

 and diminution of the mass. " The uplift and destruction were 

 simultaneous." It was proposed in brief that the destruction and 

 breaking up of the coast was contemporary with its ascension. The 

 erosion theory and the glacial theory have been involved in the wide 

 discussion in the literature, as, also, may be said of the depression 

 theory. It may be objected to each of these that it uses an agent 

 which is more or less accidental as a primary cause and makes no al- 

 lowance for the nature of the rock or material structure of the coast 

 and also fails to explain the remarkable parallelism of fjord struc- 

 tures. ^Moreover, as has been indicated in the literature quoted, 

 there are numerous other places to be observed where the present 

 structure of the lithosphere would produce a fjord coast if it were 

 to come in contact with marine erosion ; the Grand Canyon area, 

 also the canyons of the Yellowstone and indeed the parallelism of 

 small stream valleys such as may be seen in the Appalachian folds 

 near Harrisburg, for example, possess the necessary physical struc- 

 tures to produce a parallel indentation of the coast, supposing that 

 some agent of erosion, such as glaciation, were to be involved. 

 Glaciation then and marine erosion are to be regarded as accidents, 

 not as the primary cause of fjord coasts. Even if we assume that 



18 Op. cit., page 579. 



