the Revolutio7is ivhich have taken place on the Globe. 247 



where they are in general but slightly removed from their 

 original horizontal position. Such are also the transition rocks, 

 so rich in organic remains, of Dudley and Gloucestershire, 

 which appear to have been deposited at the foot of the pre- 

 viously elevated mountains of Wales, and which are them- 

 selves only affected by dislocations of a more recent date. 



Such would also appear to be a part of the transition beds 

 of Southern Ireland, known by the recent researches of Mr. 

 Weaver. This distinguished geologist remarks that some 

 parts of the system resemble, both in mineralogical and zoo- 

 logical characters, the rocks of Tortworth in Gloucestershire. 

 The principal rock masses in the South of Ireland are com- 

 posed of grauwacke, quartz rock, and limestone; they con- 

 tain crinoidal remains, Trilobites, Orthoceratites, Ellipsolttes, 

 Ammo7iites, Euomphalites, Twbinites, Neritites, Melanites, and 

 several species of Terebratula, Spirifer, Producta, and other 

 bivalves, Hi/sterolites, and many genera o'i Polyparia. The 

 anthracite and accompanying pyritiferous strata are charged 

 with the remains or impressions of plants, belonging chiefly 

 to the genera Equisetum and Calamites, with traces of i^i^- 

 coides. 



The transition rocks of the Bocage (Calvados) and the in- 

 terior of Britanny bear a great resemblance to those described 

 by Mr. Weaver in the South of Ireland. They are like them 

 composed of numerous beds of slate, grauwacke, quavtz rock, 

 and limestone, containing fossils of the same class, and pre- 

 senting mines of anthracite. 



Finally, I am induced to refer to the same epoch the slate 

 and grauwacke rocks with anthracite (worked for profitable 

 purposes, and which contain vegetable impressions differing 

 but little from those discovered in the coal-measures), which 

 form the S.E. angle of the Vosges, and which appear to rest 

 against the granitic masses of the environs of Gerarmer, Re- 

 miremont, and Tillot; masses which probably were themselves 

 raised at the formation of the old N.E. and S.W. lines of 

 elevated strata. Independently of the geological relations 

 which are apparent between the different parts of the vast 

 deposit of transition rocks above noticed, they have also in 

 common remained unaffected by the ancient N.E. and S.W. 

 system. 



When these beds are not horizontal, they are dislocated 

 in directions the most marked of which, probably produced 

 immediately after their deposit, is comprised between an 

 E. and W. line and one E. 15° S. and W. 15° N. Thus 

 tlie masses of granite and porpl)yry which, in the S.E. part 



of 



