206 M. de Beaumont 07i the Temperature of the 



schatka are composed of a similar rock, the volcanos of North 

 America are probably similarly constituted. A distribution so 

 extensive and so remarkable seems sufficiently to justify the 

 name of Andesite^ under which this compound of predominating 

 albite and little hornblende has already been sometimes men- 

 tioned. 



The object of the present memoir is to shew anew, that ele- 

 vation-craters are not volcanos ; that the distinction between the 

 two is well grounded and important ; and that even the cones 

 of volcanos can he formed only by sudden elevation^ and never 

 by the building up of streams of lava. — Poggendorff's Anna- 

 len, vol. xxxvii. p. 169. 



On the Temperature of the Eai^th^s Surface during the Ter- 

 tiary Period. By M. Elie de Beaumont. 



In the last Number of this Journal (page 177), we inserted 

 an abstract of M. Deshayes"* Memoir on the Temperature of the 

 Tertiary period, communicated to the Academy of Sciences of 

 Paris ; and we now give an account of some interesting observa- 

 tions on the same subject, read by M. Elie de Beaumont to the 

 Philomathic Society of Paris. The author stated that he had 

 for some time been occupied with the investigation of the tem- 

 perature of our latitudes during the different geological periods, 

 and that, in regard to the Plastic clay and the calcaire grossier, 

 he had concluded that the temperature was rather less elevated 

 than that deduced by M. Deshayes. According to the latter 

 naturalist, the basin of Paris must have possessed, at the epoch 

 of the calcaire grossier, a temperature at least equatorial — that 

 is to say, at least amounting to 27i° C. {8T F.) M. Elie de 

 Beaumont is of opinion, that, agreeably to the results obtained 

 some years ago by M. Adolphe Brongniart, the climate of our 

 countries, during the more ancient tertiary period, must have 

 resembled exceedingly, in its general relations of temperature, 

 that of Lower Egypt, of which the mean temperature at Cairo 

 is 22° C. (72° F.) He founds his calculation on the following 

 considerations : At the epoch of the Plastic clay and the calcaire 

 grossier, the arborescent ferns and cycadeae which had previous- 



