detained by the sea being frozen, and waiting for the next season to melt the ice."[292] [Footnote 289: So he tells us himself: "Quo cum venissent, nullum hominem, neque christianum neque paganum, invenerunt, tantummodo fera pecora et oves deprehenderunt, ex quibus quantum naves ferre poterant in has deportato domum redierunt." _Descriptio Groenlandiae_, apud Major, p. 53. The glacial men had done their work of slaughter and vanished.] [Footnote 290: "Ma la maggior parte sono delle Islande." Mr. Major is clearly wrong in translating it "from the Shetland Isles." The younger Nicolo was puzzled by the similarity of the names Islanda and Eslanda, and sometimes confounded Iceland with the Shetland group. But in this place Iceland is evidently meant.] [Footnote 291: This application of the hot water to purposes of gardening reminds us of the similar covered gardens or hot-beds constructed by Albertus Magnus in the Dominican monastery at Cologne in the thirteenth century. See Humboldt's _Kosmos_, ii. 130.] [Footnote 292: Major, _op. cit._ p. 16. The narrative goes on to give a description of the skin-boats of the Eskimo fishermen.] [Sidenote: Volcanoes of the north Atlantic ridge.] [Sidenote: Fate of Gunnbjoern's Skerries, 1456.] [Sidenote: Volcanic phenomena in Greenland.] This mention of the volcano and the hot spring is very interesting. In the Miocene period the Atlantic ridge was one of the principal seats of volcanic activity upon the globe; the line of volcanoes extended all the way from Greenland down into central France. But for several hundred thousand years this activity has been diminishing. In France, in the western parts of Great Britain and the Hebrides, the craters have long since become extinct. In the far North, however, volcanic action has been slower in dying out. Iceland, with no less than twenty active volcanoes, is still the most considerable centre of such operations in Europe. The huge volcano on Jan Mayen island, between Greenland and Spitzbergen, is still in action. Among the submerged peaks in the northern seas explosions still now and then occur, as in 1783, when a small island was thrown up near Cape Reykianes, on the southern coast of Iceland, and sank again after a year.[293] Midway between Iceland and Greenland there appears to have stood, in the Middle Ages, a small volcanic island discovered by that Gunnbjoern who first went to Greenland. It was known as Gunnbjoern's Skerries, and was described by Ivar Bardsen.[294] This island is no longer above the surface, and its fate is recorded upon Ruysch's map of the world in the 1508 edition of Ptolemy: "Insula haec anno Domini 1456 fuit totaliter combusta,"--this island was entirely burnt (i. e. blown up in an eruption) in 1456; and in later maps Mr.