188 Reviews — Alph, Favres Geological Researches 



particularly the older, are more expanded, and have been less 

 subjected to disturbances and change, the time has now come, when 

 even this, the most complicated tract of the whole chain, is to a 

 great extent laid open with clearness. 



The Alps, as a whole, have only in truth been brought into a true 

 geological order of succession by a long series of patient investiga- 

 tions, particularly during the last forty years, as carried out by a 

 number of hard-working geologists, of all countries ; and M. Favre 

 has now accomplished for his portion of the chain that which Pro- 

 fessor Studer has more particularly elaborated for the great central 

 or Swiss masses of the range. 



In the last century the chain of Mont Blanc, with its flanks, was 

 viewed as of primitive age, and this error has been dispelled by the 

 successive labours of numerous explorers. Among these Brochant 

 led the way in 1808 in his able work on the Tarentaise, wherein he 

 showed that a great part of the supposed primary rocks were of 

 Neptunian or sedimentary origin, including rocks of Carboniferous 

 and Liassic age ; and, long after M. Elie de Beaumont, extending his 

 excellent Geological Map of France into Savoy, showed the vast 

 extension of the Liassic deposits. 



In correlating the disjecta membra of the chain of the Alps as a 

 whole with their true equivalents in less disturbed regions of the 

 globe, our countrymen have also played a fair part. In 1820, Buckland, 

 after a summer's tour, boldly dashed off his general views as to the 

 great " Alpine Limestone," representing in its range most of the 

 Secondary rocks ; and though necessarily very incomplete, these 

 generalisations were at the time striking evidences of the power of 

 that eminent geologist. ^ 



But of all the earlier English writers on the structure of the Alps, 

 no one threw so much light on the Savoyard portion of the region 

 as Bakewell. In his ''Travels in the Tarentaise" (1820-22), this 

 author not only instituted comparisons with known British forma- 

 tions, but he clearly showed that chemical changes took place on 

 a stupendous scale by the transmutation of mountain masses of 

 stratified limestone into gypsum and dolomites. 



In 1827, Murchison hit off an exact definition, which remains 

 correct to the present day, by showing on the southern flanks 

 of the Alps, north of Bassano, the existence of a regular order of 

 succession from the massive Oolitic or Jurassic rocks of the chain 

 through the Cretaceous, the latter being symmetrically flanked by 

 the Nummulitic and younger Tertiary deposits of the north of Italy. 



In the meantime, struggling with considerable difficulties, Boue 

 had been constructing maps and descriptions of large portions 

 of the Austrian Alps, which, considering the want of good geo- 

 graphical materials, did that indefatigable geologist infinite credit.^ 

 Sedgwick and Murchison explored together a large portion of those 

 same Austrian Alps in 1829, and were so far successful, whilst dis- 

 puting (not always with justice) some of the conclusions of Boue, 



^ Annals of Philosophy. 



2 Boue was the first to publish a geological" map of Scotland, anno 1820. 



