532 Pro/ J-. W. Judd—On Volcanos. 



volcanic peaks, comparable in magnitude and parallel in position 

 with the range which now forms the western boundary of the great 

 American continent. Of this great volcanic chain we trace the 

 structure of portions still unsubmerged in Franz Josef Land, 

 Spitzbergen, Greenland, Jan Mayen Island/ Iceland, the Faroe 

 Islands, the Hebrides, the North-East of Ireland, the Azores, 

 Canaries, and Cape de Verde Islands, Fernando Neronha, Ascension, 

 St. Helena, and Tristan d'Acunha, in some of which eruptive action 

 is wholly extinct, while in others it still retains a considerable 

 degree of vigour. 



From this great Atlantic volcanic band there extended in Miocene 

 times one great branch to the westwards running through the 

 Arctic Archijoelago, and two great branches stretching eastwards ; 

 one of these latter being situated on the northern side of that great 

 zone of subterranean movement which now forms the mountain 

 axis of the Eastern Continent, and the other lying on the southern 

 margin of the same disturbed district. 



The northern volcanic chain was constituted as follows. In what 

 is now the Auvergne rose the vast trachytic and phonolitic cones of 

 the Mount Dore, the Cantal and Mount Mezen, so well described by 

 the late Mr. Poulett Serope; each a lofty mountain comparable to 

 Etna in its proportions. Following a line parallel to a great curve 

 of the Alpine main axis we are conducted by the smaller outbursts 

 of the Black Forest and Gdenwald to the district of the Lower 

 Rhine. Here the greatly denuded masses of the Siebengebirge, 

 the Wester wald, the Habichtswald, and the Ehon-gebirge, with the 

 less ruinous mass of the Yogels-gebirge, indicate the existence of 

 vast volcanic cones in the Miocene period, not inferior in dimensions 

 to the three great volcanos of the Auvergne. The series, interrupted 

 for a short distance by the great lateral axis now forming the ranges 

 of the Thuringer Wald, the Franken Wald, and the Fichtel Gebirge, 

 is continued by those two giant volcanos of Bohemia, now in their 

 ruined state constituting the Duppaner Gebirge and the Leitmeritzer 

 Gebirge, the latter of which is cut through by the Elbe. Again 

 following an inflexion of the great Alpine axis, and crossing the 

 lateral range of the Carpathians, we reach the Hungarian series of 

 volcanos, and recognize the evidence of gigantic Miocene cones or 

 groups of cones in the mountains of Gran and Visegrad, the district 

 around Schemnitz, the Matra, the Tokay-Eperies Mountains, the 

 Vihorlat Mountains, the Hargitta Mountains, the Transylvanian 

 Erzgebirge, and the volcanic districts of the Banat of Hungary and 

 Northern Turkey. In the southern extremity of the Crimea, in the 

 Caucasus, and in the volcanic rocks forming the southern extremity 

 of the Oural, we trace the extension of the same line of Miocene 

 volcanos till it is finally lost in the mists that still enshroud the 

 geology of Central Asia. 



^ Mr. Major has shown that there is ground for believing that a series of old rocks 

 mentioned in some old sailing directions as existing midway between Iceland and 

 Greenland, and called Grumbjorns Skerries, Avere blown up by a volcanic eruption in 

 1456, and long after that date formed a reef which has since diminished greatly in 

 height. Here then we probably have another relic of this submerged chain of 

 volcanic peaks. 



