738 report — 1884. 



r^s^r- (Unconformable on the Old Cape Schists and 

 Slates and on the Bokkeveld Beds.) 

 Devonian. 3. Bokkeveld Beds, 1,100'. 



o — ^{Probably unconformable to the Malmesbury 

 Beds.) 

 Silurian ? 2. Malmesbury Beds, Micaschists and Slates of the Cape. 



(Probable unconformity.) 

 1. Narnaqualand Schists and Gneiss. 



"Mi. Stow's Old Rocks of the Vaal, and his Kaap or Cauipbell-Randt series, in 

 Griqualand-West and the Transvaal, are probably Lower-palaeozoic, or even of 

 greater age (like Nos. 1 and 2). 



5. On the more Ancient Land Floras of the Old and New Worlds. 

 By Principal Sir W. Dawson, C.M.G., LL.D., F.B.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 sub-aquatic 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 meagre. The fact that Eopteris has 

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

 some verticillately-leaved plants allied to Annularia, the lmmble Acrog-ens of the 

 genus Psilophyton, and the somewhat enigmatical plants of the genera Pachytheca, 

 Prototaxites, and Berwynia, with some uncertain Lycopods. We have thus at 

 least forerunners of the families of the Asterophylliteee, the Lyeopodiacece, and the 

 Coniferce. 



The comparison of the rich Devonian or Erian 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 Erian, and there is a remarkable correspondence 

 of these in countries so wide apart as Scotland, Belgium, Cauada, Brazil, and 

 Australia. Examples of this were given in the Rkizocarps, at this period very 

 important, in the Lycopods, the Equisetacene, the Ferns, and the Conifers. The 

 number of coniferous trees belouging to Dado.vylon and allied genera, and the 

 abundance of ferns, often arborescent, were especial features of 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 dis- 

 tinct 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, present- 

 ing, however, some curious local differences and dividing lines which are begin- 

 ning 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 important 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 Acrogens, 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 vegetation known to- 

 have existed. 



In the Erian and Carboniferous there seem to have been two great waves of 

 plant-life, proceeding 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 Palasozoic period presents a great unity and 



