226 DR JAMES GEIKIE ON 
again, too, the under part of a basalt-rock would present a highly broken and 
jumbled appearance—crystalline, compact, and non-amygdaloidal rock being 
commingled with highly vesicular and honeycombed fragments, but all welded 
together so as to form one solid mass. 
Many of the.anamesites are more or less distinctly columnar. Good examples 
of such are seen in the Trangjisvaag district, i the valley above Howe and 
along the sea-coasts. In Kvannafield these columnar rocks break up into 
fantastic walls and isolated peaks and tors not unlike ruined masonry. Even 
when true prismatic and columnar structure is wanting, the rocks are yet 
traversed by well-marked vertical joints, which, as will be pointed out 
more fully afterwards, greatly assist the denuding agents in their work of 
destruction. 
The beds appear to vary much individually in thickness, but I think 40 
to 70 feet would be a good average. Some, however, were certainly not 
over 30 feet thick, while others may have reached and even exceeded 100 
feet. We did not trace out any one particular bed to see how far it would 
extend, but could quite well follow the lines of bedding along the slopes of 
the hills, and could thus carry the outcrop of a particular anamesite for a 
distance of several miles. The rocks, however, have so much in common that 
I doubt whether in most cases one could surely identify the same bed in 
different valleys, unless the outcrop itself were actually followed. The aname- 
site overlying the coal-beds appeared to be one and the same flow, for 
wherever we examined it the rock showed a very similar character—the only 
differences being merely such as frequently can be traced in closely adjoining 
portions of one and the same rock-mass. And this is equally true of the 
anamesite upon which the coal-bearing strata repose. The separate flows, 
however, thicken and thin out, and although I nowhere in Suderéde chanced 
to come across the terminal portion of a sheet, yet I have no doubt that those 
beds which did not measure more than 12 or 15 feet in thickness were 
merely the attenuated terminal portions of much thicker flows. 
3. Bedded Tuffs.—The anamesites are usually separated from each other 
by tuff which varies in thickness from mere thin layers of a few inches up to 
beds 50 or 50 feet in thickness; in some places the tuffs are even thicker. 
These tuffs are generally fine-grained, like indurated mud, but occasionally 
they pass into a kind of tufaceous grit. They are generally of a bright brick- 
red colour, but sometimes they are grey, blue, green, and yellow. In some 
good sections they are seen to consist of alternate ribbons and bands of fine- 
grained tuff, with shattery, crumbling, fissile, shaly clays. Often, however, a 
bed of tuff will show no lines of bedding, and looks like an amorphous 
structureless mudstone. Even in such beds, however, it will often be found 
that the tuff splits most readily along the plane of bedding, and a close inspec- 
