Sept. 25, 1S84] 



NATURE 



527 



vicinity of the town of Amprior on the River Ottawa. It 

 closely resembles the Norwegian rock, both in external appear- 

 ance hi! in its microscopic characters, containing hornblende, 

 scapolite, and pyroxene as essential constituents. A number of 

 amphibolites in the Museum of the Geological Survey of Canada, 

 which resemble this rock in appearance, have been sliced and 

 examined with the microscope, and one of them found to con- 

 tain scapolite in large amount. It was collected at Mazinaw 

 Lake, in the township of Abinger, and is from the same belt of 

 homblendic rocks as that in which Arnprior is situated. The 

 paper closes with a short account of some of these amphibolites. 

 The Geological Age of the Acadian Fauna, by G. F. Matthew, 

 A.M., F.R.S.C. — In this sketch an attempt is made, by com- 

 parison with the Cambrian fauna of other countries, and especially 

 of Wales, to fix moi ; exactly than has hitherto been d ne the 

 position ot the assemblage of organisms found near the base of 

 the St. John group. The trilobites are taken as a criterion for 

 this purpose. A brief statement of the position and thickness of 

 the beds is given, showing the relation of the fauna to the forma- 

 tion as a whole. It is shown that the genera and species of the 

 Acadian trilobites do not agree with those of the Menevian, in 

 the restricted application of that term now in vogue ; the great 

 with short eyelobes, and the genera Anopolenus, 

 Agraulos (= Arionellus), Erinnys, and Holjcepkalina being, so 

 far as known, absent from it. On the other hand, it shows very 

 close relationships in its genera to the Solva group fauna, 

 especially in the following species : — 



Solva Group 

 Conocoryphe solvensis, Hicks 

 Conocoryphe bufo, I licks 

 Paradoxides harknessi, Hicks 



Acadian Fauna 

 Ctenocephalus matlheioi, Hartt sp. 

 Conocoryphe clematis, Hartt sp. 

 Paradoxides cteminicus, Matthew 



As bearing on the question of the age of the Acadian fauna, the 

 development of the eyelobe in Paradoxides is referred to, and it 

 is shown that while in the Cambrian rocks of Wales the length 

 of the eyelobe is in direct relation to the age of the strata, the 

 Paradoxides of the Acadian fauna, having continuous or nearly 

 continuous eyelobes, are more primitive in their facies than those 

 of the Menevian, and agree with the species found in the Solva 

 group. The family of Conocoryphidse, restricting the name to 

 such species as those described by Corda under Conocoryphe and 

 Ctenocephalus, are a marked feature of this early fauna ; and 

 Conocoryphe has a characteristic suture not observed in the 

 Menevian genera. The Acadian Ctenocephalus also differs in 

 this respect fro .1 the Bohemian species. 



On the More Ancient Land floras of the Old and New Worlds, 

 by Principal Dawson, LL.D., F.R.S. — In the Laurentian 

 period vegetable life is probably indicated, on both sides of the 

 Atlantic, by the deposits of graphite found in certain horizons. 

 There is good evidence of the existence of land at the time when 

 these graphitic beds were deposited, but no direct evidence as 

 yet of land plants. The carbon of these beds might have been 

 wholly from subaquatic vegetation ; but there is no certainty 

 that it may not have been in part of terrestrial origin, and there 

 are perhaps some chemical arguments in favour of this. The 

 solution of the question depends on the possible discovery of 

 unaltered Laurentian sediments. The Silurian land flora, so 

 far as known, is meag e. The fact that Eop/eris has been found 

 to be merely a film of pyrite deprives us of the ferns. There 

 remain some verticillately-leaved plants allied to Annularis, the 

 humble Acrogens of the genus Psilophyton, and the somewhat 

 enigmatical plants of the genera Pachytheca, Prototaxites, and 

 Berwj nia, with some uncertain Lycopods. We have thus at 

 least forerunners of the families of the A rterophyllitea, the Lyco- 

 podiaceir, and the Coniferce. The comparison of the rich 

 Devonian or Elian flora of the two sides of the Atlantic is very 

 interesting. On both continents it presents three phases — those 

 of the Lower, Middle, and Upper F.rian — and there is a remark- 

 able correspondence of these in countries so wide apart as Scot- 

 land, Belgium, Canada, Brazil, and Australia. Examples of 

 this were given in the Rhizocarps, at this period very important, 

 in the Lycopods, the Equisetaceae, the Ferns, and the Conifers. 

 The number of conife ous trees belonging to Dadoxylon and 

 allied genen, and the abundance of ferns, often arborescent, 

 were especial features in the Middle and Later Erian. The flora 

 of the Erian age culminated and then diminished. In like 

 manner that of the succeeding Carboniferous period had a small 

 commencement quite distinct in its species from the Erian ; it 

 culminated in the rich vegetation of the true coal formation, 

 which was remarkably similar over the whole world, presenting. 



however, some curious local differences and dividing lines which 

 are beginning to become more manifest as discovery proceeds. 

 In the Upper Carboniferous the flora diminishes in richness, and 

 the Permian age is, so far as known, one of decadence rather 

 than of new forms. Great progress has recently been made by 

 Williamson and others in unravelling the affinities of the coal- 

 formation plants, and we are on the eve of great discoveries in 

 this field. Throughout the Silurian the conditions do not seem 

 to have been eminently favourable to plants, but the few forms 

 known indicate two types of Acr gens, and one leading to the 

 Gymnosperms, and there is no reason to doubt the existence of 

 insular land richly clothed at least with the few forms of vegeta- 

 tion known to have existed. In the Erian and Carboniferous 

 there seem to have been two great waves of plant-life, proceed- 

 ing over the continents from the north, and separated by an 

 interval of comparative sterility. But no very material advance 

 was made in them, so that the flora of the whole Palaeozoic 

 period presents a great unity and even monotony of forms, and 

 is ve y distinct from that of succeeding times. Still the leading 

 families of the Rhizocarpeoe, Equisetacea, Lycopodiacece, Fillces, 

 and Conifroz, established in Paleozoic times, still remain ; and 

 the changes which have occurred consist mainly in the degrada- 

 tion of the three first-named families, and in the introduction of 

 new types of Gymnosperms and Phamogams. These changes, 

 delayed and scarcely perceptible in the Permian and Early 

 Mesozoic, seem to have been greatly accelerated in the Later 

 \ 



On the Structure of English and American Carboniferous 

 Coals, by Edward Wethered, F.G.S., F.C.S.— The author had 

 examined several seams of coal from England and America. He 

 pointed out that they were not always made up of one continuous 

 bed of coal, but often comprised several distinct beds. In the 

 case of the well-known Welsh "four-feet " seam there were four 

 distinct strata of coals, separated by clay beds of a few inches 

 thick. In the case of the "splint coal "from Whitehill Col- 

 liery, near Edinburgh, the seam presented three clearly-defined 

 beds of coal, but these were not separated by partings of any 

 kind. With a view of testing the " Spore theory " of the origin 

 of coal, as propounded by Prof. Huxley, the author had ob- 

 tained a portion of the "better-bed" seam intact for a thickness 

 of 10 inches from the top. He had examined this inch by inch, 

 by preparing thirty-three microsopic sections. At the top were 

 3! inches of dull lustrous coal, termed "laminated coal." This 

 the author found to be practically a mass of macrospores and 

 microspores. Below this there was a change in the character of 

 the seam. Spores became less numerous ; in places they were 

 scarce, the mass being made up of vegetable tissue and a sub- 

 stance to which the author gives the term "hydrocarbon." He 

 could not, therefore, support Prof. Huxley in saying that the 

 "better-bed" coal was "simply the sporangia and spore-cases 

 of plants." The assertion would, however, apply to the first 

 3J inches of the seam. The "splint coal" from Whitehill Col- 

 liery was a better example of a spore coal than the "better- 

 bed." The bottom stratum was 4 inches thick, and presented 

 a dull lustre, with thin bright layers traversing at intervals. The 

 dull portion was a mass of spores and spore-cases, but these did 

 not enter the bright layers. A vertical section cutting a bright 

 layer, bounded on either side by dull lustrous coal, showed 

 plenty of spores in the dull coal, but in the bright not one was 

 detected. The second bed in this seam was 1 foot thick ; it 

 was of a brighter lustre than the 4 inches below, but two layers 

 could be distinctly made out, one more lustrous than the other. 

 In the dullest of the two, spores were found, which, however, 

 were less numerous than in the bed below, and were also of a 

 different variety. In the bright layers the spores were absent. 

 The top bed of the seam was also 1 foot thick, and might be 

 defined as a mass of spores, chiefly microspores, except in the 

 bright layers. The American coals examined were collected by 

 the author from the Warrior Coalfields of Alabama, and from 

 near Pittsburg, Pennsylvania. The same structural affinities 

 were noticed as in the English coals, and the author therefore 

 came to the conclusion that the English and American Carboni- 

 ferous coals had a common origin. The spores in the coal from 

 both countries were closely allied. Some microspores from 

 Alabama were identical with those which occur in the lower bed 

 of the Welsh "four-feet " seam. A feature in spores obtained 

 from all the coals was the triradiate markings which they ex- 

 hibited. Whether this was to be regarded as superficial or not, 

 it was very characteristic of them, and was therefore to be con- 

 sidered in attempting to ally them with modern vegetation. The 



