12 



GEOLOGICAL MEMOIRS. 



4. Coal, having a medium thickness of about 1 metre, and called 

 a Devesa. 



5. Beds of micaceous sandstone, interstratified with clay and grey 

 psammite, all being carbonaceous. A great number of fossil Plants 

 and a few veins of carbonate of iron are found in these beds. 



6. Coal, about one metre in thickness, and called Camada do Poso 

 Alto. 



7. Beds of pudding-stone and coarse-grained micaceous sandstone of 

 a bright-yellow colour, in which occur broken pieces of rock identical 

 in character with the quartzite and slate of the fifth system. These 

 beds are called "the roof" (telhado) by the miners of the district. 



These rocks compose the first group of the coal-bearing series of 

 beds, and are all inclined about 30° to 35° towards E. 20° N. 



The second group, immediately superimposed upon the first, com- 

 prises the following beds : — 



1. Clay-slate, partly blackish grey and partly of a bright ash-grey 

 passing to a reddish colour, containing some fossil Plants ; and beds 

 of coarse-grained, micaceous sandstone passing into conglomerate ; 

 they dip from 40° to 50° towards E. 20° N. 



2. Black psammite, with large leaves of mica, passing into a fine- 

 grained, micaceous, and hard schistose sandstone, and containing many 

 fossil Plants whose forms appear to have been slightly altered through 

 the contortions of the beds. These strata alternate with beds of black, 

 bituminous, and very hard pudding-stone; and they all dip approxi- 

 mately 54 p towards E. 20° N. In them occur here and there thin bands 

 or veins of anthracite, which expand, in places, almost suddenly, to 

 form nests of as much as 6 metres in diameter, the anthracite being 

 sometimes soft and dull, and sometimes hard, with a beautifully 

 lustrous fracture. With these anthracite masses, and in contact with 

 them, occurs a very black graphitic slate. 



3. Pudding-stone, sandstone, and shale, alternating variously with 

 one another, all very hard and slightly micaceous. This subdivision 

 consists mostly of thick beds of conglomerate, in which can be dis- 

 cerned fragments of the quartzite, greywacke, and clay-slate of the 

 second, fourth, and fifth systems. The beds dip from 60° to 65° to- 

 wards E. 20° N. 



Then follow the Silurian slate and quartzite of the fourth system, 

 which dip from 60° to 80° towards E. 20° N. 



After giving some further details of the third system, the author 

 proceeds to describe the various rocks in regard to their geographical 

 distribution and mutual relations, more particularly in regard to the 

 two groups of the coal-bearing beds ; and he gives the following 

 lists of Plants found in each : — 



Fossil Plants of the First Group. 

 Pecopteris oreopteridis. 



gigantea. 



arborescens 



alata. 



Pluckeneti. 



aquilina. 



cyathea 



Pecopteris lepidorhachis. 



murieta. 



Serlei. 



cristata. 



chcerophylloides. 



Bucklandi. 



Neuropteris heterophylla. 



unita. fiexuosa. 



leptophylla. elegans ? 



