Trof. T. Rupert Jones — On the Carboniferous Sysiem. 181 



VI. — Note on the Carboniferous System in Britain. 

 By Prof. T. Eupert Jones, F.E.S., F.G.S. 



IN compariDg the relative thicknesses of the Welsh-English and 

 the Scotch Carboniferous series for lecture notes, I have found 

 it difficult to obtain from books definite statements on this point as 

 regards some groups of these strata in Scotland. After considerable 

 reading I gather the following information. 



A general section of the Carboniferous strata of Scotland shows 

 this arrangement ; — 

 Upper Coals. 

 Moor Eock or Eoslyn Sandstone. 



( Upper Limestones. 

 Carboniferous Limestone Series \ Lower Coals with Limestones. 



( Lower Limestones. 

 Calciferous Sandstone Series. 

 In the " Geological Survey Memoir on the Neighbourhood of 

 Edinburgh " Mr. Howell gives the following average thicknesses 

 for the Mid-Lothian Coal-field (p. 73) : — Coal-measures 1220 feet ; 

 Millstone-grit 340 feet ; Carboniferous Limestone series (including 

 Upper Limestones 650', Edge Coals 600', Lower Limestones 340') 

 1590 feet. The thickness of the Lower Carboniferous strata (Cal- 

 ciferous Sandstone) is not given in Prof. Geikie's portion of the 

 Memoir, but his description of the series proves it to be of great 

 amount. 



In the "East-Lothian Memoir" Prof. Geikie estimates the thick- 

 ness of the Calciferous Sandstone series at 1350 feet, as seen on 

 the coast section between Siccar Point and Thorntonloch.^ The 

 thickness of the Carboniferous Limestone series is not mentioned 

 in this Memoii-, though the usual arrangement of the Upper and 

 Lower Limestone groups, with profitable Coal-measures between 

 them, is fully described. 



In later Memoirs of the Geological Survey of Scotland many 

 details of the local thickness of the subdivisions of the Carboniferous 

 Limestone series and of the Coal-measures are given • but no estimate 

 of the aggregate thickness of the formations is ventured on. 



The grouping of the strata in the West of Scotland appears to be 

 similar to that of the Eastern side, although the Lower Carboniferous 

 series has not the same fades as that in the East. In the useful 

 " Catalogue of the Western Scottish Fossils." published by Members 

 of the Geological Society of Glasgow for the British Association 

 Meeting of 1876, the thicknesses of the different members of the 

 system, in Central and Western Scotland, are thus stated (pp. 31 

 and 32) :— 



Upper Coals and Ironstones 1500 to 1800 feet. 



Millstone-grit Series 480 ,, 900 



Carboniferous I Upper Limestone Series 480 ,, 600 



Limestone < Lower Coals and Ironstones 420 ,, 600 



Series. ( Lower Limestone Series 600 ,, 1200 



Calciferous Sandstone Series 1500 ,, 1800 



4980 ,, 6900 

 1 " Geol. of East Lothian," 1866, p. 30. 



