TRANSACTIONS OF THE SECTIONS. 87 



It had been suggested, that the fossils in question, being of a whorled form, might 

 prove to be the ClymeniiB of the Devonian rocks ; but although, according to JVlr. 

 Salter, one or two of them have a certain resemblance to that genus, and some even 

 to Goniatites, the evidence of their being chambered shells is too obscure to decide 

 the case. The principal fossil is probably an Euomphalus : it resembles the 

 Maclurea or Rapliistoma of the Lower Silurian rocks, except that the former, to 

 which it most approaches, has a dextral and not a siniscral curve. Even should 

 some of these whorled shells prove to be chambered, there is nothing about them 

 to gainsay their belonging to tL. ^Atidtes of the Lower Silurian rocks. AnotheJ: 

 fossil is certainly an Orthoceratite. 



Sir Roderick then adverted to a feature in the older series of crystalline rocks of 

 the west coast of Scotland, which still required to be more accurately defined than 

 had hitherto been done. Prof. Sedgwick and himself had formerly called attention 

 to the occurrence, near Ullapool, of a red conglomerate or coarse grit, subordinate to 

 the crystalline rocks, but which must not be confounded with the true Old Red, aa 

 developed on the north and east coasts of the counties of Caithness, Ross, Inverness, 

 Nairn, Moray, &c. During his excursion of this year. Prof. Nicol and himself sawj 

 near Inchnadampff in Assynt, a similar interposition of hard red conglomeritic grit, 

 resting unconformably on the older gneiss. He pointedly cautioned young geologists 

 not to be led away by the notion that all Scottish conglomerates made up of crystalline 

 pre-existing rocks represented the so-called old red conglomerate, and particularly 

 referred to the coarse red conglomerate of Girvan in Ayrshire, which is a part of the 

 Lower Silurian series of the south of Scotland*. Whilst, however, it is probable that 

 some of the red conglomerate of the West Highlands, which is associated with the 

 crystalline rocks, may be also of Lower Palseozoic age> it is clear that the stupendous 

 masses of red sandstone which constitute the moHntains of Applecross and Gareloch 

 are of a younger date. Positive proof of this was formerly given by Prof. Sedgwick 

 and himselfj from unconformable junctions of the two classes of rock at Ullapool 

 in the West Highlands. On the eastern coasts also, the oldest conglomerate and 

 sandstone of the Ord of Caithness clasps round the quartzose and micaceous rocks 

 of the Scarabin Hills, and is made up of the materials derived from those crystalline 

 rocks which are contiguous to it. 



From the immense length of time which must have passed in their accumulfttion> 

 the vast deposits of the Old Red Sandstone are supposed by the author to be the 

 full and entire equivalents of the Devonian rocks of the south-west of England, of 

 the Rhenish provinces, of large regions in other parts of Germany, as well as of 

 France, Spain, and other countries. He demonstrated the truth of this position 

 by citing the fact, that in Russia, where he had traced such a very extensive range 

 of rocks of this age, regularly interpolated between the Silurian and Carboniferous 

 systems, there occurred in the sflrae beds a mixture of the same species of fossil 

 fishes (Astervlepis, Dendrodus, Giyptosteus, Bothriolepis, Holopti/chius, Cricodus, 

 Pterichthys, &c.) which prevail in the north of Scotland, with the shells which charac- 

 terize the formation in the slates and calcareous type which it assumes in Devonshire. 



He then announced that, in addition to the fossils previously elaborated and 

 described by Mr. Hugh Miller and other authors, a number of plants had recently 

 been discovered, chiefly by Mr. C. Peach of Wick, but also by Mr. J. Miller and 

 Mr. Dick of Thurso, in the vety heart of the Caithness flagstones — the great fish 

 deposit of the series. Of these plants a large number of those which Mr. Peach bad 

 submitted to him seemed to be of terrestrial origin. The importance of correctly 

 determining the character of these plants will be at once seen when it is con- 

 sidered that, with the exception of the minute and rare vegetable forms detected 

 by the author in the uppermost Silurian rocks, which form a passa,ge into the 

 Devonian rocks or Old Red Sandstone, these Caithness fossils are probably the 

 oldest known and clearly recognizable land plants ; it being believed that the fossil 

 vegetables hithertb found in the so-called Old Red, chiefly occur in the upper member 

 of the systemi Such are certain plants discovered by Dr. Fleming and others in 

 Shetland and Orkney, by the geological surveyors in Ireland ; and such is the posi- 

 tion of that very remarkable and beautiful Flora, detected by M. Richter of Sahlfield 

 in Germany, which is under the description of M. Unger of Gratz f . 



* See Quart. Jouin. Geol. Sec. vol. vii. p. 152 ; and ' Siluria/ p. 160. 

 t Quart. Journ. GeoL Soc. vol. xi. p. 416 5 and ' Siluria,' p. 358. 



