of the European Rocks. 4.4.9 



similar to that which produced the others, when we consider 

 its mode of occurrence, more particularly in the Alps and in 

 Italy. 



The geological dates of the elevations of mountains is a most 

 important subject, and one on which M. Elie de Beaumont 

 read a very interesting paper, in June last, before the Institute 

 ol France*. His recent observations have tended to confirm 

 his previous remarks on four of these epochs. 1st. That the 

 Ezgeberge, the Cote d'Or, &c. have been elevated between the 

 epoch of the Jura limestone and the green-sand and chalk. 

 (Groups 5 and 4 of the annexed Table.) 2nd. That the Py- 

 renees and Apennines were thrown up between the epoch of 

 the chalk and tertiary rocks (Groups 4 and 3). 3rd. That 

 the Western Alps were raised between the tertiary epoch and 

 the first "terrains de transport" (Groups 3 and 2). 4th. That 

 still later, there was an elevation of mountains, in which were 

 comprised some in Provence, the Central Alps, &c. 



How far the igneous rocks have been connected with these 

 phjEuomena remains to be seen; but, as before stated, it is by 

 no means fair to infer that because not seen on the surface 

 they do not exist beneath. Volcanoes, properly so called, 

 both existing and extinct, seem to have exerted a minor in- 

 fluence in the elevation of strata compared with that exerted 

 by the igneous rocks which were shot up previous to the ac- 

 tion of these volcanoes. Elevations of land do however take 

 place apparently from the causes that produce volcanoes; 

 and of these the rise of land noticed in Chili by Mrs. Maria 

 Graham, in consequence of the earthquake of 1824, is a 

 striking example. 



Should the annexed Table succeed in calling the attention 

 of geologists to other divisions than those made in the infancy 

 of the science, and grounded on particular theories, one sup- 

 posmg three great epochs and a transition between the first 

 and second of these, another considering rocks divisible into 

 two great classes, a primary and secondary, the primary con- 

 taining organic remains in its upper part,— my object will, as I 

 before stated, be fully answered. We are yet acquainted with 

 so small a portion of the real structure of the earth's exposed 

 surface, that all general classifications of rocks are premature; 

 and it seems useless to attempt any others than those which are 

 comparatively local, calculated lor temporary purposes, and 

 ol such a nature as not to impede by an assumption of more 

 knowledge than we possess, the general advancement of ge- 

 ology. 



* The first part of tins |)a[)c'r has been published in the Amialcs dci Sci- 

 rnccs ^/duni/rt for .Sf|(tfilil)tT. 



iV.5. Vol.G. No. 36. Dec. 1629. 3M Ci.as- 



