2. GEOLOGICAL FEATURES OF THE PLATEAU. 
From the investigations and conclusions by A. Geikie, ! Suess 
resumes that the whole plateau region is underlain by a series of 
great magmatic chambers communicating one with another and 
being independent in their shape of the mountain chains turned up 
in earlier time, and stretching through the region in various places. 
This statement gives some reason to expect basalt flows or rocks 
associated with them a little here and there, where crustal move- 
ments of the underground were favourable to the outburst of vol- 
canic action, however these movements had sufficient amplitude to 
set down to the very great depths which enclose the magma reser- 
voirs.. The difficulty to separate older volcanic rocks associated 
with the older underground ones, from rocks belonging to the plateau, 
arises immediately, particularly where the surface conditions or the 
- outburst power was unfavourable to the spreading of lava flows, or 
these were thrown away by a later erosion. The lack of mesozoic 
or younger sediments makes the task further difficult. 
In the Atlantic region, wherever basalts belonging to this group 
are encountered, they are associated with upper mesozoic or early 
tertiary strata; even where the mainland is built up by palaeozoic or 
earlier rocks as in Eastern Greenland, a narrov coastal stripe of 
younger mesozoic or tertiary sediments nearly everywhere locates 
the geographical distribution of these basalts; on the backland 
basalt is wanted. The earlier basaltflows of Iceland are fixed as 
tertiary by intercalated fossil bearing beds, while the cone of Bee- 
renberg and the whole island of Jan Mayen seems to be of a more 
uniform cast without greater unconformities until recent time. The 
older Spitsbergen basalts (diabases) appear either as caps crowning 
the table mountains of mesozoic strata dissected by erosion, thus 
1 A. Geikie, The tertiary basalt plateau of North Western Europe. Q. J. G. S. 
52. 1896. pp. 331—406. 
