92 Carl Fred. Kolderup. 



merates and breccias on the southside (S) and on the northside 

 (N) of the area. These lines as well as the section from south 

 to north (fig. 38) show that the Devonian conglomerates, breccias 

 and sandstones have been deposited in a basin, the bottom of 

 which lay highest in the eastern part. The border between the 

 Devonian area and the underlying crystalline rocks is a thrustplane, 

 but I do not believe that the Devonian rocks have been moved far. 



As will bee seen from the descriptions and figures the base- 

 ment conglomerates and breccias show generally no stratification, 

 and pebbles have come from rocks belonging to the next neighbour- 

 hood to the basin. Helland supposed that the pebbles were trans- 

 ported by ice, but no scratches have been found. The fact that 

 the lowest part of the basement conglomerate at some localities 

 is cemented by red sandstone and that layers of red sandstones 

 have been found in the upper part of the conglomerate, makes it 

 most probable that the climate has been almost the same here 

 as in Scotland and other parts of the "red continent". I therefore 

 suppose that most of the huge masses of pebbles which we now 

 find in the basement breccias and conglomerates have been trans- 

 ported into the basin by powerful but intermittent torrents and 

 perhaps also partly by landslides. In some places we also find 

 the detritus of the underlying rock. 



The sedimentation of the series of red and green sandstones 

 shows that there at that time has begun a more regular transport 

 of finer material into the basin. The form of the grains tells us 

 that the material has been transported by means of water, and, 

 as already mentioned, it is most likely that the strata of the green 

 sandstones, which are the thickest, have been formed in the seasons 

 when the transport was the greatest. 



During the sedimentation of the upper green sandstones, 

 with only very few layers of red sandstones, the climatic con- 

 ditions may have been altered, perhaps essentially because the 

 humidity became higher. Under such conditions the sedimenta- 

 tion was quicker and the plant remains which were transported 

 into the basin would more easily be preserved. It is also in this 

 division of green sandstones that we find almost all the plants of 

 which Thursophyton Milleri is characteristic for the Orcadian 

 in Scotland, where it occurs from the Wick to the Thurso Group. 



I have tried to prove that the basement conglomerates and brec- 

 cias correspond to the Barren Group in Scotland. In „The Geology 



