Oct. 27, 1881J 



NATURE 



607 



contain a sufficiently abundant array of detailed facts to 

 justify the conclusions at which I have arrived. 



But even were this not the case, there are other impor- 

 tant considerations that cannot be overlooked. As I have 

 already hinted, we have become acquainted with a large 

 number of curious organisms, many of which are unmis- 

 takably reproductive, but respecting the botanical affini- 

 ties of which we are as yet entirely ignorant. New forms 

 present themselves in a more rapid ratio than discoveries 

 are made of the true character of older ones. Yet many 

 of these objects are so remarkable that they must have 

 constituted very important links in the chain of Pala;ozoic 

 life ; and until we learn more about them than we at 

 present know, we cannot possibly assign to them their 

 true place in that chain ; whilst their omission must leave 

 serious gaps in the succession. 



But our difficulties do not end here. All the objects to 

 which I have just refeiTed have been discovered but 

 recently. Ten years ago we knew nothing of their exist- 

 ence, and new forms are still being added to our cabinets. 

 The old fossiliferous shales and sandstones revealed no 

 traces of them. We only found them when the micro- 

 scope came to be applied to the calciferous nodules of 

 Oldham and Halifax. Our first supply of special types 

 was derived from the former locality. The examination 

 of the Halifax nodules revealed the e.xistence of several 

 new forms, though obtained from the same geological 

 horizon and from localities but a few miles apart. Arran 

 and Burntisland have, in like manner, contributed types 

 wholly unknown in Yorkshire and Lancashire, and the 

 French localities of Autun and St. Etienne (where also 

 are found Carboniferous plants of which all the structure 

 is preserved) have each their own characteristic forms.' 

 We thus learn that so far as these six special localities 

 are concerned, whilst certain common features characterise 

 their floras, each locality has, as in living floras, genera or 

 species peculiar to itself. Now we chiefly know the full 

 extent of the localisation of these six Carboniferous floras 

 from their accidental preservation in calcified or siliceous 

 deposits, and not from the revelations of the ordinary 

 fossiliferous shales and sandstones. But we cannot sup- 

 pose that the six localities enumerated are the only ones 

 that possessed floras peculiar to themselves. Does not 

 common reasoning justify the suggestion that all Car- 

 , boniferous plant-bearing localities would exhibit similar 

 features, had their fossils been preserved as they are at 

 Halifax or at St. Etienne ? If so, seeing how widely 

 Carboniferous deposits are diffused throughout the world, 

 what myriads of minute, but phytogenetically important 

 forms of plant-life must have existed of which we are 

 absolutely ignorant — an ignorance that can only be 

 diminished by the discovery of other localities as pro- 

 ductive as the six that I have enumerated. 



But even were we perfectly acquainted with the Car- 

 boniferous flora, we should not be much nearer the end. 

 Beyond the fact, established by Dr. Dawson, that in the 

 Devonian age a flora existed almost, if not wholly, as rich 

 as the Carboniferous one, a flora in which Gymnosperms 

 existed with as high an organisation as characterised the 

 similar Carboniferous types, what do we know respecting 

 the minuter forms of this flora, which correspond to those 

 which I have described from the Coal-measures ? But 

 can it be doubted that such objects must have e.xisted in 

 abundance ? Still less can it be supposed that so rich 

 and highly organised a flora as that of the Devonian age 

 first sprang into existence during that age. That flora 

 must have been preceded by one rich in types of a lower 

 terrestrial vegetation than is represented by the ferns — 



* I telieve that this fact partly explains the unwillingness of the French 

 palaeontologists to accept our English views as to the close affinities existing 

 between the Lepidodendra and the Sigillarise. The peculiar Diploxyloid 

 forms of Lepidodendron, i.e. those which possess the outer exogenous zone 

 which the French botanists regard as characteristic of, a Sigillarian stem, 

 appear to be absent from the beds of Autun and St. Etienne, as they are 

 rare in Canada and the United States. In Great Britain, on the other hand, 

 they constitute, with several variations of specific detail's, our prevailing 

 type. 



the Lycopods and the Dadoxylons of the Devonian beds 

 of North America. But what do we know of this earlier 

 flora ? Almost nothing. The remains of pre-Devonian 

 plants now known are so obscure that little reliance can 

 be placed upon them. Eophyton is rejected from the 

 vegetable kingdom by Nathorst, and most of the other 

 so-called Fucoids of the Palaeozoic strata are of almost 

 equally dubious nature. Where more definite forms of 

 what may probably be Marine .Algie do occur they come 

 too late in time to avail in the construction of the Palaeo- 

 zoic pedigree. Even the Liassic CJtoiidraitcs hellensis of 

 the Lias cannot be depended upon with absolute cer- 

 tainty. It is only when we reach the Tertiary age that 

 we find the Delesseriae and Halymenites in shapes that 

 leave little rcom for doubting their true nature. Yet our 

 French friends trust to these dubious objects as being 

 real Fucoids, and as such, the ancestral predecessors of 

 the higher Cryptogams of the Devonian and Carboni- 

 ferous ages. So long as this ignorance and uncertainty 

 remain, it seems to me that we cannot construct, with 

 any degree of probability, the genealogical tree of Palaeo- 

 zoic plant life. 



As to the many detailed conclusions arrived at by MM. 

 Saporta and Marion, I will only refer to two or three 

 statements in addition to the more important ones to which 

 I have already called attention. Thus Mr. Gardner's 

 abstract states that " eight still existing Diatoms have 

 been discovered in British Coal." I thought that I had 

 thoroughly exploded that fallacy in my Memoir, Part X. 

 MM. Saporta and Marion conclude that Asterophyllites 

 was a floating or procumbent plant allied to the Equise- 

 tacea:, thus following M. Renault in separating it from 

 Sphenophyllum, which the authors believe to be a Rhizo- 

 carp allied to Salvinia. I see no ground whatever for these 

 conclusions. They further consider that some of his 

 Calamari£e(Equisetace3e)were heterosporous. They arrive 

 at this conclusion from my discovery that Calamostachys 

 Binneana, which I believe to be a fruit of an Asterophyl- 

 litean plant, was a heterosporous Strobilus ; but I wholly 

 demur to the idea that either the plant or the fruit was 

 Equisetaceous. 



For the reasons above given, I doubt whether even my 

 valued friend the Marquess Saporta, highly accomplished 

 as I know him to be, will be able to " make clear the pre- 

 cise lines through which the evolution of the one from the 

 other [/(•. the Phanerogams from the Cryptogams] has 

 been accomplished." Wm. C. Williamson 



Owens College, Manchester, October 14 



THE INTERNATIONAL EXHIBITION AND 



CONGRESS OF ELECTRICITY A T PARIS » 



V. 



THE labours of the jury are now finished, and the dis- 

 tribution of medals took place on Cictober 21 at the 

 Conservatoire des Arts et Mi^tiers. It is understood that 

 they have been somewhat liberal in their distribution of 

 honours, and have endeavoured to make things pleasant 

 all round. Indeed the time allotted to them for investi- 

 gation being postponed for a week at the beginning, and 

 afterwards cut short by a week at the end, was quite in- 

 sufficient to settle the burning question which is the best 

 of all the electric lights. 



The diploma of honour {diplonie d'honneiir), which is 

 the highest award of all, has been voted to Dr. Werner 

 Siemens, Sir William Thomson, Mr. Edison, M. Gramme, 

 Prof. Graham Bell, Prof. Hughes, Prof. Pacinotti, Prof. 

 Bjerknes, M. Gaston Plants, M. Baudot, and M. Marcel 

 Deprez, the last-named being the inventor of a system of 

 distribution of electricity which has found much favour in 

 Paris. M. Baudot is the inventor of a multiple printing- 

 telegraph. The Exhibition has been announced to close 

 on November 15, but there is some talk of a later date. 



* Continued from p. 5S9 



