216 REPORTS ON THE STATE OP SCIENCE. — ^1916. 



The Committee, having obtained a grant for this research from the 

 Royal Society, desire to be reappointed to carry on investigations 

 regarding points which are still doubtful. 



Note by Dr.. IVLackie. — As the members of the ' Older Series ' show locally 

 intrusion and alteration by the younger granites of the North of Scotland, they 

 probably represent an older stage of Old Red Sandstone than the other beds of 

 the Rhynie outlier. 



Report on the Plants. By Dr. Kidstox, F.R.S. 



From a palseobotanical point of view the results of these investiga- 

 tions are of gi'eat interest and importance. A careful examination of 

 the Rhynie chert zone has shown that it is composed of a number of 

 peat-heds, attaining a thickness of 8 feet, whose foniiation was brought 

 to a final close by infiltration with silica, supplied by geysers or 

 fumeroles. The structure of the peat and its enclosed plants, in many 

 cases, are preserved in great perfection. The condition of the silicified 

 peat, so far as its structure and contents are concerned, is shown to-day 

 very much as it existed at the time that its formation was brought to a 

 close. The peat-beds, now the chert zone, lie on a bed of white clay, 

 4 feet thick, the top inch of which is a grey clay. 



It contains two vascular plants, Rhynia Gwynne-Vaughani n. sp. 

 and n. g. , and Asteroxylon Mackiei n. sp. and n. g. The plants, named 

 Rhynia, grew closely crowded together, and their remains formed a 

 peat. The plant was rootless, consisting entirely of a system of 

 cylindrical stems. Rhizomes were fixed in the peat by rhyzoids, and 

 tapering aerial stems gi^ew up from them. These stems bore small 

 hemispherical projections, and branched dichotomously and laterally. 

 They had a thick- walled epidermis with stomata, and a simple central 

 cylinder consisting of a strand of tracheides suiTOunded by phloem. 

 Large cylindrical sporangia, containing numerous spores, were borne 

 terminally on some of the leafless aeiial stems. The plant is com- 

 parable with some of the specimens of PsUophyton princeps, figured 

 by Dawson ; and a new class of vascular cryptogams, the Psilophytales, 

 is formed for their reception. This is characterised by the sporangia 

 being borne at the ends of the branches of the stem without any relation 

 to leaves or leaf-like organs.' 



The peat is almost entirely formed of Rhynia, while Asteroxylon is 

 of very rare occurrence. 



" Kkynia Gvnjime-Tdvqhani was described by Dr. R. Kidston and Professor 

 Lang in a paper read before the Royal Society of Edinburgh on July 3, 1916. 

 The description of Asteroxylon Mackiei, K. and L., is reserved for a future 

 communication. 



