J. W. Judd — On Volcmios, 201 



It is not our purpose to discuss in these chapters tlie general 

 phenomena connected with the formation of the Alpine chain. This 

 has recently been done in a most able manner by Professor Suess of 

 Vienna, in his "Die Entstehung der Alpen." Our object will be 

 rather to study the relations between the manifestations of subterra- 

 nean force which have, during such comparatively recent geological 

 periods, resulted in the striking mechanical and chemical changes in 

 the Alpine strata, and those others which have produced the numerous 

 volcanic outbursts within and around the Alpine system. And we 

 believe that these studies of the orographic features of our own 

 ■continent will lead us to conclusions, similar to those arrived at by 

 Darwin from his observations in South America — namely, that the 

 causes of the elevation of continents and of the upheaval of mountain 

 chains are but different modes of action of the same forces which 

 give rise to volcanic outbursts. 



"We must here, however, carefully guard ourselves against an error 

 into which some of the older geologists fell. Although the eleva- 

 tion of surrounding areas often precedes and accompanies the out- 

 bursts of volcanic forces, and the actual accumulation of ejected 

 materials around igneous vents may result in the formation of 

 mountain piles of the vastest dimensions, yet the origination of the 

 principal mountain chains does not appear to be directly referable to 

 volcanic action. On the contrary, a period of volcanic activity in a 

 district would seem to be almost invariably followed by a greater or 

 less amount of subsidence of the immediate area in which it takes 

 place. Von Buch, when he came to study the interesting volcanic 

 rocks situated in the very heart of the Alpine chain — namely, those 

 of the Southern Tyrol — fancied that he had discovered in them the 

 real cause of the elevation of the Alps. The fallacy of the views of 

 Von Buch has, however, been fully shown by the proofs which have 

 been since obtained, that the volcanic eruptions in question"^ took 

 place at a period long prior to that of the movements to which the 

 origin of the Alps must be attributed. 



But although the outbursts of these volcanic rocks of the Southern 

 Tyrol were certainly not the direct cause of the elevation of the 

 Alpine chain, it would be a great error on our part to hastily adopt 

 the conclusion that the two series of events had no connexion with 

 one another. 



So far as we are able to judge from the characters of the faunas 

 of the Silurian, Devonian and Carboniferous rocks of Southern 

 Europe, there is no reason whatever for concluding that during these 

 periods any kind of barrier to the distribution of organic life 

 occupied the position of the existing Alpine chain. Indeed, the first 

 indication of the^existence of a line of weakness in this portion of 

 the earth's crust is found towards the close of the Permian period, 

 when a series of volcanic outbursts on the very grandest scale took 

 place, along a line parallel to and nearly coincident with the main 

 axis of the present Alpine range, and were continued with some 

 interruptions till nearly the close of the Triassic period. Of the 

 nature, products, and attendant phenomema of these pre-Alpine 



