Scrope's Memoir on the Geohgy of Central France* 369 



platform appears as a precipitous curtain-like range, broken by recesses in- 

 to short, deep, and massive formations, in which all the rude and stupen- 

 dous scenery of a primitive mountain district is displayed in its full mag- 

 nificence. There we have the grand scenery of the Apennines, with all 

 the luxurious vegetation of the finest chesnut forests. It is, therefore, a 

 striking contrast to observe the six perfect volcanic cones of Montpezat, 

 Burzet, Thueyts, Jaujac, Souillols, and Ayzac, perched at distant inter- 

 vals on the rocky ridges of these granitic embranchments. For an account 

 of these volcanic cones we must refer the reader to Mr Scrope's work. 



In summing up the principal facts in the history of this district, as dis- 

 closed by its present appearances, Mr Scrope refers them to four epochs. 



1. The primary elevation of the high nucleus of central France above 

 the ocean which deposited the secondary strata, by which a large protu- 

 berant mass of crystalline rock, with massive and laminar (granite, gneiss, 

 and mica schist) was erupted in a solid state, and superficially exposed the 

 incumbent secondary strata, apparently sliding away by a lateral move- 

 ment on all sides towards the lower level. 



2. After that occurred an era marked by the abundant deposition of 

 calcareous strata from a series of fresh water lakes, occupying the irregu- 

 lar hollows of that elevated district, and probably overflowing from the 

 highest to the lowest levels ; while, at the same time, numerous eruptions 

 of volcanic matter, both trachytes and basalts, were taking place at inter- 

 vals from these principal habitual sources, as well as from some minor 

 Tents. 



3. This state of things seems to have been at length disturbed by a se- 

 cond paroxysmal elevation of the same immense continental tract, compre- 

 hending both the primitive platform and the overlying fresh water forma- 

 tions. By this the barriers of the lake basins being burst, their contents 

 were discharged upo» the lower levels, in one or more sudden debacles, 

 •which produced extensive denudations throughout the valleys of the Al- 

 lier and Loire by the force of the escaping water, and perhaps deposited 

 the vast accumulation of diluvial matter observable along the course of 

 these rivers in the departments of the Allier, Nievre, and Cher. 



4. To this epoch succeeded a period of occasional volcanic eruptions, 

 chiefly of separate openings on the longitudinal fracture line, accompa- 

 nied by the continual deepening and widening of the vallies of the district 

 by ordinary excavating forces ; a period which the apparent extinction of 

 the volcanic vents cannot be said to have terminated, since some of these 

 bear all the appearance of very recent activity, and render it by no means 

 incredible that their phenomena may again be renewed at no distant date. 



From this brief and general abstract of Mr Scrope's work, the geological 

 reader will perceive how much pleasure awaits him from a perusal of the 

 work itself. To a general reader, even not versant in geological details, 

 the admirable coloured engravings which accompany the work will convey 

 much curious information, and they will, we are persuaded, induce many 

 an ordinary traveller to visit the interesting district which they represent. 



As our friend and coadjutor Dr Hibbert is now on his way to examine 



