628 REPORT — 1901. 



Mr. Wilson, and the oil-shale fields in the Lothians have been mapped by 

 Mr. Cadell. An important memoir by Sir A. Geikie on ' The Geology of Central 

 and Western Fife and Kinross' has just been issued by the Geological Survey, in 

 which the structure of these coal-fields is described. Mr. Cadell lately gave an 

 account of the geological structure of the oil-shale fields in his presidential address 

 to the Edinburgh Geological Society. 



Within the period under review detailed researches of great importance on the 

 fossil flora of British Carboniferous rocks have been carried out by Mr. Kidston, 

 to which reference ought to be made. The results are of the highest value for 

 correlating the strata in diiferent areas.' By means of the plants he arranges the 

 Carboniferous rocks of Scotland in two great divisions : a lower, comprising the 

 Calciferous Sandstone and Carboniferous Limestone series; and an upper, including 

 the Millstone Grit and the Coal-measures, there being a marked palaeontological 

 break at the base of the Millstone Grit. He shows that the upper and lower 

 divisions of the system, not only in Scotland but in Britain, are characterised by a 

 different series of plants, not one species passing from the lower division — save in 

 tlie case of Stigmaria —into the upper. From his researches it appears that, among 

 ferns, Neuropteris is all but unknown in the lower division, whereas in the upper 

 it is very abundant. The Sphenopterids are proportionately common in both 

 divisions ; but those of the lower are usually characterised by cuneate segments, 

 while those of the upper have generally rounded pinnules. Alethopteris, so 

 common throughout the whole of the upper series, is entirely absent from the 

 lower. The genus Calamites, which is extremely plentiful in the upper, is almost 

 entirely absent from the lower division, where its place is taken by Asterocalamites. 

 The Cordaitem are also rare below the Millstone Grit, though very plentiful above 

 that horizon. Siffillaria, so rare in the Lower Carboniferous rocks, is extremely 

 abundant in the upper division, and particularly in the middle Coal-measures. In 

 short, Mr. Kidston concludes that the floras of the two main divisions of the 

 Carboniferous system, though belonging to the same types, are absolutely distinct 

 in species, and in the relative importance of the genera. 



By means of the fossil plants Mr. Kidston correlates the Coal-measures of 

 Scotland underlying the red sandstones with the lower division of the Coal- 

 measures of England, and the overlying red sandstones of Fife with the middle 

 division of the English Coal-measures. 



It is remarkable that the evidence supplied by the fossil fishes has led 

 Dr. Traquair independently to a similar conclusion. He holds that fossil ichthyo- 

 lof^y proves the existence of only two great life-zones in the Carboniferous rocks 

 of'Central Scotland— an upper and a lower — the boundary line between the two 

 being drawn at the base of the Millstone Grit. The Scottish Carboniferous rocks, 

 Ijeino- mostly estuarine, give an opportunity of comparing the estuarine fishes of 

 both'divisions. He finds the Coal-measure fishes of Scotland to be the same as 

 those in the Englisii Coal-measures, while those occurring below the INIillstone 

 Grit in Scotland are mostly different in species, and often, too, in genera, from the 

 forms above that horizon. 



Of special interest as bearing on the former extension of this system in Scot- 

 land is the discovery made by Professor Judd- in 1877 of a patch of Carboniferous 

 sandstones and shales, with well-preserved plant remains in Morven. Another 

 small outlier of this formation has recently been found in the Pass of Brander by 

 the Geological Survey.^ -ri ^ xt 



The reptiles from the Elgin sandstones, recently described by Mr. E. T. Newton,* 

 add fresh interest to the study of these rocks. The structural relations of these 

 sandstones have been fully treated by Professor Judd in his great paper on the 

 Secondary Rocks on the east of Scotland,' and again in his presidential address 



' ' On the Various Divisions of British Carboniferous Rocks as determined by their 

 Fossil Flora,' Proc. Roy. Fhys. Soo. Edin., vol. xii. p. 183 (1893). 

 - Q)iart. Journ. Geol. Soc, vol. xxxiv. p. 685. 

 ' Summary of Proqress, Gcoloyical Survey, 1898, p. 129. 

 * PMl. Trans., vol", clxxxiv. p." 431 (1893) ; ihid., vol. clxxxv. p. 573 (1894). 

 » Quart. Journ. Geol. Soc, vol. xxix. p. 98. 



