6. The later Arctic expeditions have established the existence of vast volcanic formations in the high north, and of very recent deposits in their depressions. In fact, a vast volcanic zone seems to extend from East Greenland, through Iceland, Jan Mayen and Spitzbergen, to Franz-Josef Land. The geological features of the latter are at any rate in harmony with those of North-east Greenland. The tertiary Brown-coal sandstone of East Greenland is also found in Franz-Josef Land, though Brown-coal itself is met with only in small beds, which, nevertheless, may be reckoned among the many indications that the climate of Polar lands must once have been as genial as the climate of Central Europe at the present day. The kind of rock which predominates is a crystalline aggregation called by the Swedes “Hyperstenite” (Hypersthene), identical with the Dolerite of Greenland; but the Dolerite of Franz-Josef Land is of a coarser-grained texture, and of a dark yellowish green colour; according to Professor Tschermak (the Director of the Imperial Mineralogical Museum at Vienna), it consists of Plagioclase, Augite, Olivine, titaniferous Iron and ferruginous Chlorite. The mountains of this system forming table-lands, with precipitous rocky sides, give to the country we discovered its peculiar physiognomy. 7. The Dolerite of Franz-Josef Land greatly resembles also the Dolerite of Spitzbergen. After the return of the expedition I saw in London some photographic views of the mountains of North-East Land, Spitzbergen, taken by Mr. Leigh-Smith, and I was at once struck with the resemblance between their forms and those of Franz-Josef Land. I learnt also from Professor Nordenskjöld, the celebrated explorer of Spitzbergen, as I passed through Sweden, that the rock of North-East Land was this same Hyperstenite (Hypersthene). Hence the geological coincidence of Spitzbergen and Franz-Josef Land would seem to be established; and this geological affinity, viewed in connection with the existence of lands more or less known, appears to indicate that groups of islands will be found in the Arctic seas on the north of Europe, as we know that such abound in the Arctic seas of North America. Gillis’ Land and King Karl’s Land are, perhaps, the most easterly islands of the Spitzbergen group; for it is not probable that these and the lands we discovered form one continuous uninterrupted whole.