ANNIVERSARY ADDRESS OF THE PRESIDENT. 



lxvii 



He divides his memoir into two parts, the first treating of the 

 Ardennes, and the second of the Rhenish strata, and adheres to 

 the same principles of subdivision which characterized his first work ; 

 adopting for the Ardennes the following systems from below upwards : 

 1st, the Devillian, 2nd, the Revinian, and 3rd, the Salmian, the 

 names being all derived from special localities ; and for the Rhenish, 

 1st, theGedinnian, 2nd, Coblentzian, 3rd, the Ahrian, also local names. 

 The Ardennes and Rhenish formations are all composed of quartz- 

 slates, quartz rocks, grits, &c, and underlie the Anthracitiferous 

 formation, which M. Dumont subsequently subdivided into three 

 systems, the Eifelian, the Condrusian, and the Coal, so that the 

 Devonian was here confounded with the Carboniferous in one forma- 

 tion characterized merely by its carbon constituent. M. Dumont 

 exhibited the same mineralogical skill in the examination of all these 

 rocks, and the same care in describing his different systems, which, 

 as they closely resemble each other, must have caused him great 

 trouble. The various contortions of rocks he notices are also 

 sufficient to indicate the complexity of the district ; but he mani- 

 festly considers the question of fossils as one of secondary import- 

 ance. M. Dumont in 1838 referred to his former determination of 

 the correlation of the Eifel formation with the Anthracitiferous for- 

 mation of Belgium, and stated that he had subsequently visited 

 Wales in company with MM. D'Omalius d'Halloy and De Yerneuil, in 

 order to determine in a similar manner the correlation of the English 

 and Belgian strata ; and he comes to the conclusion that the divisions 

 established by Sedgwick and Murchison, as Cambrian and Silurian, 

 correspond with the Slate and Anthracitiferous formations of D'Hal- 

 loy : on this supposition he considers the Slate -formation of Belgium 

 as the representative of the Cambrian formation, and the Anthraci- 

 tiferous formation as including the whole of the Silurian system and 

 the Carboniferous formation in the following order : — 



j Upper Lime- 

 stone. 



Anthraci- 

 tiferous 

 Formation. 



Limestone 



Dolomite 



Limestone. 



=} 



Carboniferous 

 Limestone. 



(Old Red, supposed to be absent in Belgium.) 



Grit Upper Ludlow. 



Limestone Aymestry Limit. 



Upper Quartz 



•Slate. 



Lower 

 Limestone. 



{ 



Slate with sub-"] 



ordinate Lime- v. Lower Ludlow. 



stone J 



Limestone 



Dolomite , 



Limestone , 



}Wenlock 

 Limestone. 



> 



I 



Lower Quartz! 

 Slate. 



Slate 

 Formation 



f Grey Fossilife- 



Wenlock Strata. 



Caradoc and 

 Llandeilo. 



ion. 



rous Schist 

 Schist and red" 

 Grit, conglome- 

 rate Grit,Quart- 

 zite, Schist ... 



Upper "1 



Middle I Cambrian System. 



Lower .........J 



Silurian 

 System. 



