2i6 KKiD'i.ioi- N.\.\sr:,\. M.-N. Kl. 



Fig. 164. 1 Lunna Holm and the Islands west of Lunna Ness. II Out Skerries with the 

 Lighthouse. The height of tiie highest islands is 52 metres above the sea. August 26, 191 1. 



Fig. I (^"3. the west side of Bressay in the background). On some of the 

 islands similar formations are. noticeable, a low outer border and hij^^her 

 ridges inside (see Fig. 164). 



In Yell Sound at Ollaberry Bay, on the east coast of Xorthmavine 

 (in the northernmost portion of Mainland), I found, by levelling, the plane 

 of the supposed strandfiat to be about 33 metres above the sea. The is- 

 lands Bigga and Samphrey in the middle of the sound are 33 metres and 

 30 metres above sea-level. 



If this low- land may actually be considered to be a regular strandfiat 

 of the same kind as the Norwegian strandfiat, it seems probable that the 

 slopes of the hills inside have been much changed by subacrial denudation 

 and perhaps by glacial erosion after the formation of the strandfiat. 

 During the periods when the strandfiat was developed, the shore erosion 

 by frost was probably not very effective in this region, so near the warm 

 Atlantic Current, where the climate was probably not very cold. Hence 

 the strandfiat was not cut very broad, and as its formation took a long 

 time, the surface of the land was at the same time to a comparatively 

 large extent affected by the subaërial denudation. 



There is no well-developed submerged sirandflat along the shores of 

 the Shetland Islands. Along a great part of the coast the sea-bottom 

 slopes gradually from the shore down to depths of 100 metres and more, 

 without any distinct break or well marked edge. At many places there 

 are, however, indications of a submerged narrow platform, less than 15 

 or 20 metres below sea-level. They may be as much as i kilometre broad 

 and are bounded by a somewhat steeper slope outside. 



Considering the exposed situation of these islands to a stormy sea, 

 and the comparatively small power of resistance of their rocks to erosion, 

 it may seem remarkable that there is not a better developed emerged or 

 submerged strandfiat along their coasts. 



It proves: — on the one hand, that the wave action alone has not much 

 power to form a strandfiat. and on the other hand, th.at there cannot 

 have been much shore erosion bv frost for its formation in this region. 



