Recent Work in the Hardanger District. 77 



The overthrust mass contains not only the oldest granites an^ 

 gneisses, but also masses of Teleinark formation, and even some of 

 the Cambro-Silurian schists, all folded up together. 



These overthrust rocks were described by Kjerulf under the name 

 Hoiefjeldskvarts and by Brogger as the " Yngre Gneisformation,"^ 

 and the probability that their position is due to overthrusting was 

 not definitely stated by those authors. 



In the south-western part of the Hardanger Vidde there is- 

 a large area of the overthrust rock extending on the high ground 

 from above Odde to above Koldal, and on a line parallel to the 

 nbrth-eastern boundary of this tract there is a row of high peaks, 

 the lower part of each consisting of Cambro-Silurian and the summit 

 of a mass of the overthrust rock. Mr. Kekstad found that these 

 mountains capped with the blocks of overthrust rock rest each in 

 a hollow in the Cambro-Silurian, for in evei'y case he noticed on 

 going round one of them the schists dip on all sides towards that 

 particular peak. 



The Younger Granite. 



Hitherto it does not appear to have been known that any of the 

 granite in this district was newer than the Cambrian, for though 

 the Telemark formation is penetrated in all directions by granite 

 veins none have hitherto been recorded as cutting the Cambro- 

 Silurian. 



Mr. Kaldhol has now, however, found that the granite of the 

 Suldals Fjeld is of two ages, and on the south of the little lake by 

 the Skardnut he noticed granite cutting the schists and altering them 

 into hornfels. In other places there are bed-like patches of granite 

 in the schists, in the neighbourhood of which there is a distinct 

 false lamination, and small fragments of schist occur in the granite. 

 This younger granite is of medium grain, with very little sign of 

 foliation. 



Faults. 



The rocks of the district are intersected by numerous faults, and 

 the influence of these faults on the surface features is discussed at 

 some length. The valleys of the district may be divided into twa 

 classes: (1) the wide open valleys of the high ground; (2) the 

 fjord -valleys, by which we mean the great valley of the Hardanger 

 Fjord itself and its branches. The bottom of these fjord-valleys 

 is now in part submerged beneath the water of the sea and in part 

 above sea-level. In many cases the fjord-valley has been excavated 

 along the bottom of one of the older wide open valleys of the 

 high ground. 



The river Bjoreia flows for many miles through one of the wide 

 open valleys of the Hardanger Vidde, and at the great waterfall 

 Voringfos it plunges into a fjord-valley, the Maabddal. 



In the Tear Book for 1900 Dr. Keusch suggested that the position 

 of the waterfall and the direction of the Maabodal were due to faults, 

 cracks, or lines of weakness in the rock in which the valley has 

 been cut ; and in the Year Book for 1903 Mr. Eekstad deals with the 



