INTRODUCTION.

THE island of Iceland is situated in the Atlantic Ocean, on the confines of the polar circle, between 63° 24′ and 66° 30′ of north latitude, and between 13° 15′ and 24° 40′ in longitude west of Greenwich.

The opinion, that this island owes its formation to the operations of submarine volcanoes, is not only confirmed by analogical reasonings deduced from the appearances presented by other islands, which are confessedly of volcanic origin, but gains ground in proportion to the progress of a closer and more accurate investigation of the geological phenomena which every part of it exhibits to the view of the naturalist. In no quarter of the globe do we find crowded within the same extent of surface such a number of ignivomous mountains, so many boiling springs, or such immense tracts of lava, as here arrest the attention of the traveller. The general aspect of the country is the most rugged and dreary imaginable. On every side appear marks of confusion and devastation, or the tremendous sources of these evils in the yawning craters of huge and menacing volcanoes. Nor is the mind of a spectator relieved from the disagreeable emotions arising from reflection on the subterraneous fires which are raging beneath him, by a temporary survey of the huge mountains of perpetual ice by which he is surrounded. These very masses, which naturally exclude the most distant idea of heat, contain in their bosom the fuel of conflagration, and are frequently seen to emit smoke and flames, and pour down

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upon the plains immense floods of boiling mud and water, or red-hot torrents of devouring lava.

The principal volcanoes are: the Öræfa, Skaptâr, Kötlugiâ, Solheima, Myrdal, Torfa, Eyafialla, Arnarfell, Eirik, Bald, Blâfell, Geitland, Snæfell, Drânga, and Glâma Yökuls or ice mountains; Krabla, Hrafntinnufiall, Leirhnukr, Biarnarflag, Hitahol, Hrossaborg, Herdabreid, Sniâfiall, Trolladyngiar, Kerlingafiall, Hekla, Skialldbreid, Skardsheidi, Henglafiall, and the range of mountains which stretch from thence to Cape Reykianess, near which an old submarine volcano was in action not many years ago. There exists, besides, an immense number of smaller cones and craters, from which streams of melted substances have been poured forth over the surrounding regions. Of these volcanoes, Krabla, Leirhnukr, Biarnarflag, Hitahol, Hekla, and the Kötlugiâ, Solheima, Öræfa, and Skaptâr Yökuls have keen active in the course of last century. The first four are situate in the northern division of the island, near the lake Myvatn, and are supposed to have some subterraneous communication with each other. The rest lie in nearly a direct line along the southern coast.

Tracts of lava traverse the island in almost every direction. The most extensive fields are those in the volcanic regions around Myvatn. The northern and eastern shores of that lake are completely covered with lava; it abounds with islands consisting of the same substance; and a dreadful torrent has been poured down the river which it supplies, into Reykiadal, Adaldal, and the plain on the eastern margin of the Skialfandafliot. Another stream appears to have flowed down Bârdardal, along the western margin of the same river, from some volcano in the interior. A considerable stretch of melted substances is also met with to the north-east of Husavik; and on the east side of the large Yökul river, which falls into the Axarfiord, another melted tract runs through the parish of Presthol. To the east of Krabla, and the sulphur mines of Reykiahlid, a large stream of lava stretches into the interior, where the Fremri or more distant sulphur mines are situated, the vicinity of which also consists of lava ;