160 AMTLND HELLAND ON THE FJORDS, LAKES, 



392 metres. The mountain of Tronfjeld, in Osterdalen, consists of 

 gabbro, in which are small quantities of serpentine ; the summit is 

 1744 metres above the sea, and 150 metres below this, on the western 

 slope, a rounded block of granite was found. Boulders of laminated 

 quartzite with rounded edges occurred up to a somewhat greater height, 

 so that the upper limit of erratics is here about 1600 metres. The 

 height of the bottom of the valley of Osterdalen is about 500 metres. 

 Erratics of serpentine, laminated quartzite, and granite are found on 

 Solen Mountain in Rendalen * : this mountain consists of red sand- 

 stone, paragonite schist, and conglomerate, the height of its summit 

 being 1788 metres. According to Mr. Tornebohm's measurement, 

 boulders occur to within 47 metres of the summit, or up to 1741 

 metres above the sea. The height of the country below this mountain is 

 about 700 metres. Suletind Mountain in Yalders is 1770 metres high ; 

 according to Keilhau an erratic is found on its summit. The height 

 of Utrovand Lake (985 metres) may be taken as the general height 

 of the country at the foot of the mountain. In South-eastern 

 Norway, where the mountains are much lower, boulders, of course, 

 cannot be observed at heights like the above ; but on Graagalten 

 Mountain, above Lake Soneren, I found erratics up to the summit, 

 756 metres above the sea, the elevation of the lake being 118 

 metres. On the mountain of Skrimfjeld, south of Kongsberg, erratics 

 occur up to the summit and roches moutonnees near to it ; this is 900 

 metres, the height of the country below being about 250 metres. 



Assuming, then, that no important changes in configuration 

 have taken place since the transportation of the boulders, we have 

 the approximate minimum thickness of the glaciers given in the 

 following Table : — 



Thickness of the Glaciers during the Glacial Epoch. 



metres. 



Height of the groovings in the isle of Varaldso 569 



Depth of the Hardanger Fjord inside the isle 631 



Thickness of the glacier in the Hardanger Fj ord 1 200 



Height of erratic boulders in the Sulends 511 



Depth of the Sogne Fjord inside the Sulends 1244 



Thickness of the glacier in Sogne Fjord 1755 



Height of groovings above Aurlands Fjord 606 



Depth of this fjord 275 



Thickness of the glacier in Aurlands Fjord 881 



Height of groovings above Sor Fjord 471 



Depth of this fjord 392 



Thickness of the glacier in Sor Fjord 863 



* Toraebohm, "Om flyssblock och terasser," Geol. Foreningens Forh. vol. i. 

 and Schlotz," Sparagmitkvarts-fjeldet," Nyt Mag. f. Naturw. vol. xx. 



