N. Plant — The Brazilian Coal Fields. 147 



feetj remained empty (see Volcanos, p. 261). Such facts as these 

 have brought me to the conviction that though there may be occa- 

 sionally lateral flows of lava beneath the surface of a volcano, from 

 an interior pool, through fissures opening outwards at a lower level 

 — as in the tappings of the lake of Kilauea, so frequently witnessed 

 — yet, in general, lava solidifies so rapidly and readily from in- 

 crease of pressure or diminution of temperature, that no very exten- 

 sive accumulations of such matter in a fluid state are likely to exist 

 even beneath an active volcano, still less below vaster areas of the 

 earth's crust, and that the apparent connection of one volcanic vent 

 with others in its neighbourhood, or belonging to the same chain, is 

 rather due to the lateral transmission or escape of heat than to the 

 actual transference of liquid matter between one and the other. 

 This is the leading idea which I have ventured to enounce in the 

 work on volcanos so often referred to ; and it is, I believe, perfectly 

 consistent with all that we know of the phenomena of occasional 

 local excitement and intermittence in the volcanic subterranean forces. 

 It is an attractive sensational idea — that of a molten interior to the 

 globe underlying a thin superficial crust, its surface agitated by tidal 

 waves and flowing freely towards any issue that may be here and 

 there opened for its escape ; but I do not think it can be supported 

 by any sound argument based on ascertained facts or phenomena, 

 and I prefer the supposition that the interior of the globe, like its 

 surface, is solid, except where local and temporary increase of heat 

 or reduction of pressure have given occasion to the local liquefaction 

 and partial outward discharge of the expanded matter — changes 

 which may be attributed to the unequal escape of heat from the 

 interior into outer space, both by radiation from a surface of ever- 

 varying oonductibility, and by direct expulsion through hot springs 

 and volcanic vents. 



Fairlawn, Cobham, 



March Uth, 1869. 



II. — The Brazilian Coal Fields. 



By Nathaniel Plant, F.R.G.S., F.G.S., etc. 



"With a Description of the Plant-Remains, etc., by"W. CARRtrTHBRS, F.L.S., F.G.S., 

 of the British Museum. 



THE presence of Coal-beds in South America has been known for 

 several years, but the only localities on this side between the 

 Amazon and the Eiver Plate where their existence has been actually 

 determined, are in the two extreme southern provinces of Brazil, 

 Eio Grande do Sul, and in the adjoining one of Santa Catherina, and 

 in the neighbouring Eepublic of Banda Oriental or Uruguay. 



Lignite, brown-coal, and bituminous schists occur in thin beds 

 along the coast and in the interior of Maranham and Minas Geraes ; 

 but it is only in these three southern provinces that true Carboni- 

 ferous rocks containing palaeozoic fossils have hitherto been dis- 

 covered ; nor should I think it likely, from the observations I have 



