2/2 HISTORY OF GEOLOGY AND PALAEONTOLOGY. 



volcanic rocks by subsequent denudation have been treated 

 with no less careful observation and insight. 



In the course of his researches, Geikie did not confine 

 himself to the Scottish volcanoes of Tertiary age. The first 

 volume of his important work treats the older volcanic rocks 

 of Great Britain from the Pre-Cambrian to the close of the 

 Permian period. Geikie does not admit any essential differ- 

 ence between old and modern volcanoes, and he judges all 

 massive outpourings, sills and dykes, homogeneous bosses and 

 cones, from this standpoint. On the one hand, the phenomena 

 of past periods are read in the light of recent manifestations 

 of volcanic action; and vice versa, the stratigraphical relations 

 of the submarine tuffs and massive outbreaks of the Palaeozoic 

 era are used to elucidate certain of the recent phenomena 

 which are removed from present observation. In this volume, 

 examples are described of typical stratified volcanoes in the 

 Silurian and Devonian formations of Wales and Scotland, the 

 extensive fissure-eruptions of the Carboniferous epoch in 

 Scotland, and the scattered homogeneous domes or tuff-cones 

 which took origin in England during the same epoch. In the 

 Mesozoic period, Great Britain was marked by almost com- 

 plete cessation of volcanic activity. 



The volcanic phenomena of the Faroe Islands have been 

 investigated by Professor James Geikie (1880), Amund Helland 

 (1881), Breon (1884), and Lomas (1895). These islands 

 display a close relationship with the northern areas of Great 

 Britain. 



Important contributions to our knowledge of volcanicity 

 have been made by Dr. Hermann Abich, in his works on the 

 geology of the Caucasian areas. The Persian volcano 

 Demavend has also been made the subject of geological 

 researches, the Austrian geologist, Dr Tietze, having given 

 the most recent account in 1878. Reports of the extinct 

 volcanoes of Asia Minor appear in several books of travel 

 published about the middle of the nineteenth century; the 

 volcanoes in the vicinity of the Dead Sea have been examined 

 in some detail by Blanckenhorn and Diener. 



In Asia proper, volcanic activity is at present concentrated 

 along the eastern coast-line, on the borders of the Pacific 

 Ocean. The volcanoes in Kamtschatka, in the Aleutian and 

 Kurile Isles, in Japan, Formosa, and the Philippines, have 

 been repeatedly described in geographical and geological litera- 



