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XXIV. — On Old Red Sandstone Plants showing Structure, from the Rhynie Chert 

 Bed, Aberdeenshire. Part I. Rhynia Gwynne-Vaughani, Kidston and Lang. 

 By R. Kidston, LL.D., F.R.S., and W. H. Lang, D.Sc, F.R.S., Barker Professor 

 of Cryptogamic Botany in the University of Manchester. (With Ten Plates.) 



(MS. received July 10, 1916. Read July 3, 1916. Issued separately February 27, 1917.) 



Introduction. 



The chert of the Muir of Rhynie, containing plant-remains, was discovered by 

 Dr W. Mackie of Elgin while investigating the sedimentary and volcanic rocks of 

 Craigbeg and Ord Hill which occur in that area.* The original discovery was made 

 on loose specimens, built into the dykes or scattered over the fields, especially those 

 lying to the north of the road which runs from Rhynie to Cabrach, and east and 

 west of the right-of-way that here connects Windyfield Farm with the public road. 



Our investigations have so far shown that only two vascular plants occur in the 

 deposit. A transverse section of a stem of each of these was figured in Dr Mackie's 

 paper, but the plants were neither named nor described. We have named the plant 

 that occurs in greatest abundance Rhynia Givynne-VaughaniJ after our late friend 

 Professor D. T. Gwynne-Vaughan, who, it had been hoped, would have been con- 

 cerned with the investigation of these fossils. A full description of this plant is 

 given in the present paper. 



The second vascular plant has been named Asteroxylon Mackiei, after Dr Mackie, 

 the discoverer of the original specimens.} This plant has so far been found only 

 in a few isolated patches among the remains of Rhynia. The description of 

 Asteroxylon Mackiei and certain other vegetable remains is reserved for a later 

 communication. 



As it was uncertain whether the isolated plant-containing blocks of chert, some 

 ot which were 2 feet in diameter, were derived from the Old Red Sandstone or from 

 another series of rocks, Mr D. Tait, acting on instructions from Dr Flett, dug three 

 trenches in the lower field between Easaiche Bridge and Windyfield farmhouse. § 

 In one of these trenches the chert was found in situ. By some the section exposed 

 was not thought to be conclusive as to the age of the chert bed, and to enable this 

 to be determined beyond doubt, grants were received from the British Association 

 and the Royal Society of London to defray the expense of having additional trenches 

 dug on a more extended scale. 



The work was again put under the supervision of Mr D. Tait, when more com- 



* W. Mackie, " The Rock Series of Craigbeg and Ord Hill, Rhynie, Aberdeenshire," Trans. Edin. Geol. Soc, 

 vol. x, pp. 205-236, pi. xxii. 



t Mackie, I.e., pi. xxiii, fig. 5. + Mackie, I.e., pi. xxiii, fig. 6. § Mackie, I.e., p. 223. 



TRANS. ROY. SOC. EDIN., VOL. LI, PART III (NO. 24). Ill 



