114 (KIDI.Idi- N.WSKN. M.-X. Kl. 



Fig. 105. Islanc 



(lcscril)C(l l)y i )r. Kcuscli as cliaraclcristic <»f llie stranilflat, is often seen 

 even on small islets ami holms. 



T measure»] the heii^'hts of tlie strandflat on the southern and s'juth- 

 westcrn side of Haroi to be between 17 and 25 metres ai)ove the sea, 

 on the west coast of Alien Island 28 metres, and on the small Dronen Is- 

 land, witli the mountain Droneliatten in the nuddle, 18 metres. These 

 islands are northeast of Alesunrl. and the heij^hts were measured with 

 sextant from off the coast of J^^jortoft Island, where I was lying at anchor 

 on Aug'ust 22nd, 1909. Owing to the distance the measurements cannot 

 be expected to be very accurate. 



The Borgund Fjord, just south of Ålesund, is narrow and fairly well 

 sheltered against the open sea outside. Tliere is none the less a well 

 developed strandflat along the northern coast of Suloi, and on the islands 

 in the fjord (Fig. 106). 



The mainland as well as the islanrls in the region of Ålesund are 

 formed of fairly resistant rocks, generally supposed to be Archæan, but 

 lately by J. Schetelig [1913] maintained to be younger eruptive gneisses 

 of the great Caledonian "folding-ditch" of Northern Norway. The low 

 parts of the row of islands north of Ålesund — including Giskoi, Aalderoi, 

 \"igra, Lepsoi, Haramsoi, Flemsoi, Fjortoft, and Haroi — are to some 

 extent built up of quaternary (glacial) material. But the strandflat de- 

 scribed above, is largely cut in solid rock. 



From the seaward coast of these islands submerged platforms, with 

 hundreds of rocks and shoals in or slightly below sea-level, extend 7 to 

 10 kilometres out into the sea. 



It is a noteworthy fact that the sul)merged platforms with sunken 

 rocks and shoals are much broarler in these northern regions than any- 

 where along the Norwegian coast further south. Advancing along the 

 coast northeastwards and northwards we will find the submerged strand- 

 flat increasing still more in wirlth. 



This striking difference in the development of the submerged strand- 

 flat cannot be explained l)y a difference in the geological structure of 

 the coast, because in this region the coast is built up of very much the 

 same kind of what is supposed to be Archæan rocks, as in many places 



