RECENT STUDIES IN THE GEOLOGY OF THE FAEROES 41 



100 m — in the central area in the west. It decreases in thickness with in- 

 creasing transgressivity in the east, where the peripheral part of the sill is 

 locally almost perpendicular. It is most Ukely that the Fugloy sill and the 

 Svinoy sill (Fig. 6) belong to the same intrusive formation, later on divided 

 by the Fugloyarfjordur. The thickness of these sills is only 15 to 30 m. 



As is evident from what is said above we find a morphologically common 

 feature in these sills, a characteristic semi-saucer-shaped form. The sills run 

 rather concordantly in the central area, where they reach their greatest thick- 

 ness, while in the peripheral area they become strongly transgressive, at the 

 same time decreasing considerably in thickness. 



Dykes. Dykes occur everywhere, but are most abundant along a belt running 

 NE.-SW. across the northern group of islands. They represent roughly the 

 same main types as are found in the plateau basalt. The course of the dykes 

 is usually a straight fined, but sometimes rather winding. It looks as if the 

 feldspar dykes have a more winding course than the dense, dark basalt dykes. 

 General thickness is 2 to 4 m; the greatest thickness observed is 20 m. Geikie 

 (1880) gives the main direction as NNE.-SSW. and ENE.-WSW. Noe-Nygaard 

 (1940) proves that the dominating direction of 76 dykes on Kallsoy and 

 Kunoy is NNE.-ENE. to SSW.-WSW. On Suduroy the main orientation is 

 approximately NW.-SE. 



After the intrusion of irregular intrusive formations, sills, and dykes, there 

 occurred again a tectonic period. 



If we draw a line from Mykines to Fugloy, it will hit the deepest points 

 in the straits and the greatest heights in the valleys running in the direction 

 of the straits. North of this fine the dip is roughly towards the ENE., and 

 south of this fine it is approximately ESE. The fine thus forms the present 

 main water-shed of the islands. 



On western Mykines the dip is 13°, on eastern Mykines 8°, on western 

 Vagar 3°, on StreymoyandEysturoy2°-3°, andon the northern islands the dip 

 is even smaller. This indicates a movement along the fine with upheaval of the 

 land to the west. By this movement fracture fines and "lamellae zones" have 

 arisen in the plateau — running NE.-ENE. north of the fine and SE.-ESE. 

 south of the fine — and where they cross dykes, horizontal dislocation of the 

 dykes are visible in the direction of the "lameUae zones". Thus the movement, 

 which has resulted in the above-mentioned water-shed in the plateau, is 

 younger than the dyke intrusion and consequently is Late Tertiary. 



While the Tertiary geology of the Faeroes in recent years has been the 

 object of a systematical geological mapping, the Quaternary geology has only 

 been dealt with fragmentarily. 



As already shown by Helland (1880) and Geikie (1880) the Faeroes had a 

 glaciation of their own. The aforementioned hinge-line (the water-shed of the 



