10 p. A. Øyen. 



To explain the rather great percentage of laccolite- 

 rocks in the moraine, we only have to remember the 

 extensive area of those rocks on both sides of the true 

 north-south line, crossing the Lake of Maridalsvand and the 

 moraine here in question. And, in connection with this fact, 

 it is also highly interesting to see, that out of one hundred 

 stones no less than sixty-four derived from a territory lying 

 between thirty kilomètres and one hundred kilomètres north 

 of the place of deposition. As to the occurrence of porphyric 

 syenite being probably identical with that of the region of the 

 Lake of Stenbrovand it is important to see that the line 

 of motion crossing the Lakei of Stenbrovand only forms an 

 outside angle of a couple of degrees with that of the Lake 

 of Alunsjøen. 



The specimens of dyke-rocks, found in the gravel, all of 

 them indicates a removal following the true north-south line 

 with perhaps a little deviation to the south-east, as is indi- 

 cated by the syenite-porphyry of Bygdø. The fact of such 

 a deviation would be further evidenced, if some of the light- 

 coloured rocks, above mentioned, had really been that of a 

 mænaite. As to this probable fact, I am not quite sure, as the 

 bostonite of the neighbourhood of Christiania in some places 

 looks so similar, that it is very difficult to see any difference by 

 the naked eye. But there is another proof of such a devia- 

 tion having taken place; that is the occurrence of blocks of 

 camptonite in the very next neighbourhood. As we have 

 already seen, there was not found any specimen of that 

 rock in the measured portion of gravel examined. But only 

 some few hundred mètres to the east, near the bridge of 

 VoUebæk, I found some erratics of camptonite of quite the 

 same type as that occurring in several localities in Gran as 

 composite dykes accompanied by mænaite. This fact indicates 



