Iviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



on the eastern side of Gallicia, by Link in the province of Tres os 

 Montes, and by Le Play in Spanish Estremadura, and infers that 

 these also may belong to the Silurian series. 



The lithological characters of the carboniferous deposit of Val- 

 longo, thus plunging beneath beds containing organic remains re- 

 ferred to the date of the Lower Silurian deposits, are important, as 

 showing the physical conditions under which the accumulations have 

 been effected, and their general agreement with many other deposits, 

 in which sheets of vegetable matter have been so formed, as eventually 

 to have been turned into coal and anthracite, amid mud charged with 

 carbonaceous matter and beds of shingles. Why we should riot ex- 

 pect accumulations of the kind at this period, the fitting conditions 

 for the gathering together of plants or their remains, either by growth 

 on the spot or drift from their place of growth, so that they were 

 mixed with little or no common mud or other sedimentary matter, 

 does not appear. We find old mud accumulations, now forming 

 black slates, common enough in some parts of the Silurian series, 

 and there is no want of carbonaceous matter in the black slates of 

 North Wales and Ireland beneath the whole mass of the beds com- 

 monly referred to that series. 



The occurrence of the anthracite beds in the position and under 

 the conditions stated by Mr. Sliarpe, would be highly interesting in 

 itself, as showing to what extent clean or nearly clean accumulations 

 of vegetable matter may have been effected amid deposits in which 

 the carbonaceous, and, we may fairly conclude, vegetable matter was 

 generally more diffused amid mud and gravel ; but the remains of 

 fossil plants detected in connection with this carbonaceous series are 

 still more interesting, always assuming that the sections seen by Mr. 

 Sharpe are unequivocal, as his certainly would appear to be, unless 

 we suppose a most enormous reversal of these deposits. 



The remains of the plants found by Mr. Sharpe were submitted 

 to the examination of our Foreign Secretary, Mr. Bunbury, who, 

 though the specimens of ferns were in bad preservation, considered 

 that one bore a strong resemblance to Pecopteris Cyathea, of the 

 coal-measures ; another reminded him of Pecopteris muricata, and 

 a third of Neuropteris tenuifolia. Mr. Sharpe calls attention to the 

 evidence, as far as it goes, afforded by these plants, of a vegetation 

 having existed similar to that of the coal-measures at a geological 

 date long anterior to them. It would indeed be of the greatest geo- 

 logical importance to arrive at an insight into the kind of vegetation 

 that clothed the land, which furnished by its disintegration, abrasion, 

 and removal by river and breaker action into fitting places of de- 

 posit, those thick accumulations now known as the Silurian series. 

 We appear to have fair reason for concluding that, while the seas 

 swarmed with trilobites and molluscs, the dry land, supplying the 

 detritus amid which these remains were entombed, was not a desert 

 waste, a mere mass of rocks decomposing under the action of the 

 atmosphere, and worn away along the sea-level by the breakers ; in 

 fact nothing but a storehouse for the production of the marine sedi- 

 ments of the time. We require a marine vegetation as a base for 



