Recent Work in the Sardanger District. 75' 



and included patches of basic rock, of the old gneiss, and of the 

 Telemark formation are common. 



The granite platform upon which the Cambro-Silurian strata rest 

 is one of the striking features in the geology of the Hardanger Vidde. 

 It is suggested by Mr. Eekstad that this platform may possibly be 

 a pre-Cambrian surface of erosion, and in that case, as he points out, 

 it is remarkable that it should have retained its horizontality through 

 the elevation of the Scandinavian highlands and through the vast 

 period which has elapsed since. It is, however, possible that it 

 may be a thrust-plane. 



The surface of this platform is usually from 3,000 to 4,300 feet 

 above the sea so far as the Hardanger Vidde is concerned, and 

 consequently the magnificent sections which we see as we pass 

 through the valley of the fjord and its branches are in the granite, 

 the gneiss, or the Telemark formation, and it is not until we emerge 

 from the valley on to the high ground of the Vidde itself that we 

 come to the Cambro-Silurian. 



The most accessible place on the Hardanger Vidde at which the 

 junction between the granite and the overlying Cambro-Silurian 

 can be seen is the mountain Grytefjeld, above the head of the 

 Maabodal. If we mount up the zigzag path near the great waterfall 

 Voringfos we see that mountain befoi'e us when we emerge from the 

 valley. Its appearance is very remarkable. The lower and main 

 part is of a light colour, whilst on its top there is a dark cap. The 

 light-coloured rock is the granite and the cap is the Cambro-Silurian. 

 The boundary between them at this point appears to be a thrust 

 plane, for Dr. Eeusch found that the topmost part of the granite 

 was foliated parallel with that boundary. 



In some places the Cambro-Silurian strata rest upon old gneiss or 

 upon Telemark formation, but the platform usually consists of granite^ 

 In the Suldals Fjeld Mr. Kaldhol found a conglomerate which he 

 thought might be the basement-bed of the Cambro-Silurian, but at 

 the same time he saj'S it may belong to the Telemark formation, and 

 over the rest of the district there does not appear to be any basement 

 conglomerate to the schists. 



In places there is at the bottom of the schists a bed of arkose-like 

 sandstone, and in others a bed of felspathic quartzite, in each case 

 containing flakes and layers of schist. 



The Camhrian. 



The Cambro-Silurian Series is divided into three divisions, the 

 lowest of which is provisionally classed with the Cambrian and the 

 two upper with the Silurian. The lowest division consists of dark- 

 coloured schist not unlike the alum slate of the Christiania districts 

 The rock gives a black streak. It is much crumpled and contains 

 many quartz eyes. There is a good deal of finely disseminated 

 pyrites, which gives a yellow-brown colour to the weathered surface. 

 When not folded the thickness is from 90 to 150 feet. Dichjonema 

 flabelliforme, Eich., and traces of some other fossils have been 

 found in these black shales. In 'the Suldals Fjeld these black beds 

 are sometimes wantine;. 



