ANNIVERSARY ADDRESS OF THE PRESIDENT. XCIX 



The Morbihan system is also inferred to be indicated in Labrador 

 and Canada. 



Respecting the relative geological ages of the four systems noticed, 

 they are considered to be in the following order, the first being the 

 most ancient, and the third formed anterior to all the Silurian accu- 

 mulations : — 



1 . System of Finisterre. 



2. System of the Longmynd. 



3. System of Morbihan. 



4. System of Westmoreland and the Hundsriick. 

 Treating of the old slates of Brittany, whether taking the direction 



of the Finisterre, Longmynd or Morbihan systems, M. filie de Beau- 

 mont notices their envelopment, in an unconformable manner, by a 

 great deposit of sandstones and conglomerates referred by him to the 

 age of the Caradoc sandstone. M. Elie de Beaumont points to the 

 greater extension of the sea at the time of the Caradoc sandstone 

 than at the period when the previous fossiliferous beds were deposited, 

 a sea covering portions of Brittany, Scandinavia and northern Ame- 

 rica, so that the first Silurian beds in those countries were contem- 

 poraneously formed, and are referable to the Caradoc sandstone, a 

 great absence of accumulations being observable in the same regions, 

 this absence in Brittany corresponding with the double period of 

 tranquillity existing between the elevation of the Finisterre and Mor- 

 bihan systems. He then inquires respecting the evidence of a geo- 

 logical horizon of the date of the Caradoc sandstone in Wales, one 

 which has been ascertained from independent observations, during 

 the progress of the Geological Survey, and of which a notice was 

 communicated to you by Professor Ramsay and Mr. Aveline in a 

 memoir previously noticed. Taking into account the system of La 

 Vendee proposed by M. Riviere, which M. Elie de Beaumont con- 

 siders not unfounded on facts, though he is not personally acquainted 

 with them, the following is his view of the deposits of rocks and of 

 systems of elevation formed in western Europe during the earlier 

 times of the palaeozoic period. 



1. Green satiny slates of Belle-Isle. 



1. System of La Vendee. 

 (Direction, N.N.W. and S.S.E.) 



2. Cumbrian rocks of Brittany. 



2. System of Finisterre. 



(Direction, at Brest, W. 2^ 45' S. and E. 21° 45' N.) 



3. Green slates of Wales and felspar rocks. 



3. System of the Longmynd. 



(Direction, at the Binger Loch, N. 31° 15' E. and S. 31° 15' W.) 



4. Fossiliferous series of the Bala limestone. 



4. System of Morbihan. 



(Direction, at Vannes, W. 38° 15' N. and E. 38° 15' S.) 



i^2 



