256 DR JAMES GEIKIE ON 
south and south-east. In addition to that main line of drainage, there would 
of course be subsidiary water-partings, such as that which runs down through 
Stromée between Saaten and the heights that lie to the south of Thorshayn. 
From this water-shed streams would flow east in the direction of Kollefiord and 
Kalbaksfiord, and west into what is now Hestéefiord. 
4. Origin of Main Water-parting, &c.—To what the original superficial un- 
dulations of the old table-land were due it is not so easy tosay. Evidence is not 
wanting, however, which seems to show that in some cases the direction of a 
valley may have been determined by the dip of the strata. Thus in Fundings- 
fiord the dolerites dip approximately in the same direction as the fiord or 
E.N.E., and similar appearances were noted in Andafiord, where the beds 
incline to north-east. Again, on the south side of the main water-parting 
nearly all the fiords and valleys run towards the south-east, or approximately in 
the same direction as the dip. On the other hand, it will be noted that some 
of the valleys and fiords trend at right angles to the dip, particularly in Osterée 
and Suderée, while others run in a direction exactly opposite to the inclination 
of the strata. It is possible, therefore, that the coincidence of the dip with the 
trend of certain valleys and fiords may be to some extent at least accidental, 
and that the configuration of the original surface may have been determined 
only in part by the inclination of the bedding. It seems not unlikely, indeed, 
that mere irregularities in the deposition and accumulation of the youngest or 
latest of the trappean strata may have had much to do in producing the primeval 
water-sheds of the old table-land; so that, while the original streams would in 
many cases flow with the dip of the rock, they might in other cases frequently 
be compelled to run in some different direction. It is even quite possible that 
the strata may have been slightly tilted since the streams first began to carve 
out the hollows which are now land-valleys and sea-lochs. For example, the 
dolerites in the north of Osterée and Strombe may have been approximately 
horizontal or even had a slight dip towards the north-west when running water 
commenced to carve out the now submerged valley between Nordskaale and 
Eide. If the subsequent tilting were slowly effected, the erosion of the valley 
might have kept pace with the elevatory movement ; the direction of the drain- 
age need not have been reversed. But we see now such a very small portion 
of the ancient volcanic plateau that it is almost useless to speculate upon the 
various causes, for there may have been many not now apparent, which deter- 
mined the principal water-sheds of the now fragmentary table-land. MAcKENZIE 
was of opinion that the narrow channels that separate the islands might have 
originated in the destruction of large basalt-veins, removed by denudation in 
the same manner as those smaller veins and dykes which are seen giving rise 
to caves and hollows along the shore-line. The fiords, however, are as we have 
seen simply submerged valleys, and there is nothing to show that the valleys 
