12 ARCTIC BASALT PLATEAU 
sandstone of tertiary age separated by a denudation plan from the 
jurassic deposits and filling out the depressions and cavities carved 
out in these deposits by an earlier erosion. Between the two last 
mentioned sedimentary members of the series, following the plan 
of unconformity, one meets with a basalt sill of relatively great 
thickness, well exposed in steep cliffs in the middle part of the 
south-west coast, whilst the superimposed tertiary sandstone culmi- 
nates in the highest icecap-covered summit of the island. The sill 
seems to thin out in the northwestern and southeastern directions 
no basalts being reported from the hills forming the northwestern 
and southern capes of the island. Even from the northwestern 
shore, opposite the highest summit, and from the northern slopes 
of it no volcanics are reported, though deep erosional depressions 
seem to run through the island in a northeastern direction. The 
relations of the basalt to the roofing tertiary sandstone, if the con- 
tact is of igneous character or the sandstone of a transgressional 
type, are not cleared up; the former seems to be true by rate of 
the rapid outthinning of the basalt sill. 
The New Siberian Islands are relatively well Lota through the 
investigations by the late Baron Toll and-his companions, but until 
to day no general report is published and not to be expected in 
the immediate future. Some facts placed to the writer’s disposal 
may be published here. The easternmost island, the true New Si- 
beria, is covered with quaternary deposits without any afflorements 
of older rocks. Ice drifted boulders and pebbles of basalt of the 
Bennett type are common upon the shores and are also found on 
the highest elevations of the flat island. The middle Thaddaeus 
island represents similar conditions, except on the northern promon- 
tory. On the western island, Bielkoff, Kotelnyi and on the cape 
Bereshnykh of the Thaddaeus Island, palaeozoic sediments of various. 
ages are encountered, the oldest of them being developed as camb- 
tian graptolite slates on the Bielkoff Island by the west. On the 
shores of the greatest island rocks of silurian, devonian and car- 
