RIBEIRO COAL OF S. PEDRO DA COVA. 



13 



Neuropteris Villiersi 

 auriculata. 



Fossil Plants of the First Group (continued). 



Asterophyllites foliosa. 

 Annularia longifolia. 

 brevifolia. 



Sphenophyllum Schlotheimi. 



Walchia. 



Asterophyllites equisetiformis 



tuberculata. 



Calamites approximatus. 



cannseformis. 



Equisetum columnare. 

 Lepidodendron Harcourti. 



comosa. Lepidodendron Harcourti. 



With many other, as yet undetermined, genera and species, 



Pecopteris oreopteridis. 



gigantea. 



longifolia. 



affinis. 



polymorpha. 



• Grandini. 



arguta. 



abbreviata. 



Fossil Plants of the Second Group. 



Sphenophyllum Schlotheimi. 

 Cyclopteris orbicularis. 

 Lonchopteris Bricei. 

 Calamites pachyderma. 

 Poacites. 

 Knorria. 

 Lepidodendron. 

 Asterophyllites ? 

 Sphenophyllum erosum. 



With many other undetermined species. 



The Trilobite -slates of the Lower Silurian formation do not 

 everywhere border the eastern side of the coal-bearing beds. From 

 Monte Alto to beyond Cancella velha, east of Pacal, they are dis- 

 placed several hundred metres towards the east, and the rocks of 

 the coal-group rest upon those unfossiliferous slates and quartzites 

 which the author is inclined to consider as the lowest member of the 

 Lower Silurian Formation, or rather as the newest member of the 

 Cambrian. The Trilobite-slates, however, by no means underlie the 

 newer formation, for they are clearly seen at their eastern boundary 

 reposing upon the azoic slates and quartzites. This formation is 

 therefore represented, on the right bank of the Douro as well as on 

 the left, as a narrow band, which runs parallel to the coal-bearing 

 beds. It has an independent strike from N.N.W. to S.S.E., and it 

 was deposited in a basin of unfossiliferous slates and quartzites. 



The rocks of the fifth system, as exhibited in the Serra de Santa 

 Justa and near Vallongo, are next described ; and the author remarks 

 that from the structure of that " Serra " it may be easily perceived 

 that the elevation of the beds is not the result of forces which have 

 affected this mountain-range only, but has been produced by an im- 

 mense lateral pressure, which caused the slates to be folded over one 

 another in undulations, through which the fifth system lost much of 

 its original extension at the surface, and was compressed into a 

 narrower space. The strike of the granite of Oporto and Baltar being 

 parallel to that of these rocks, that is E. and W., Senhor Ribeiro 

 considers the unheaval of that igneous mass to have produced the 

 upheaval and compression already alluded to, which also affected 

 similarly the Trilobite-slates containing Calymene Tristani, C.Arago, 

 Ogyqia Guettardi, 0. Edwardsi, Illcenus Lusitanicus, I. giganteus, 

 and many other fossils, which are often distorted in consequence of 

 the disturbance which the beds have sustained. It is, however, 



