468 Dr. Wheelton Hind— The Culm of W. Germany. 



to the effect that recent investigations tend to prove that in the 

 Southern Transvaal the Wit water sr and System was deposited on the 

 pre-existing Old Granite, and that for the time being he considers 

 the question whether this granite must be regarded as intrusive in the 

 oldest sedimentary rocks as doubtful, and as direct proofs of the 

 granite being intrusive in Hospital Hill Series are wanting he suggests 

 that possibly the upper and lower series of the South African Primary 

 System are of different ages, the majority of the crystalline schists 

 being segregations and alterations by pressure from the granite. 

 Thus at first he was of the opinion that the Old Granite was intrusive 

 in the Hospital Hill Series (our present Lower Witwatersrand Beds), 

 but later felt doubt about this and reserved a final opinion. More- 

 over, in discussing Mr. Jorissen's paper,^ which I refer to later, he 

 says,- in reference to the relation existing between the Witwatersrand 

 Series, Swaziland Series, and the Old Granite, " Possibly the granite is 

 intrusive into both of these ; possibly also the granite in different 

 places may belong to separate intrusions of different ages." The 

 recent investigations which he referred to were started by the late 

 Mr. D. DorffeP in December, 1903. Until then the Old Granite was 

 generally considered intrusive in the Witwatersrand System. 

 {To he continued in our next Number.) 



Y. — The Homotaxial Equivalents of the Culm of Western 



Germany. 

 By Dr. W. Hind, B.Sc.LoncL, F.G.S., etc. 



IN the Geological Magazine, 1904, Dec. V, Yol. I, p. 403, 

 I criticized the view put forward by Dr. Parkinson that the 

 Culm beds in the neighbourhood of Marburg were of Lower 

 Carboniferous or Tournaisian age. Last summer I had the advantage 

 of being taken over the ground by Professor Kayser, of Alarburg, and 

 also of seeing his valuable and extensive collections from the Culm 

 of various parts of Germany. 



The view that the Culm of Germany is of Lower Carboniferous 

 age has naturally arisen from the fact that it certainly forms the base 

 of the Carboniferous rocks of Western Germany, and that these rocks 

 rest on Upper Devonian beds with Clymenia without any apparent 

 great unconformity. Unfortunately sections showing anything like 

 a complete sequence are unknown, and the Culm seems to have been 

 laid down in several small basins over a gradually sinking area of 

 Upper Devonian rocks, themselves much moved and interrupted by 

 volcanic outbursts, so that the lowest bed or beds of the Culm are not 

 everywhere present. 



By comparing the zonal fossils of the known sequence of the 

 Culm or Pendleside Series in either Great Britain or Belgium with 



1 " Notes on some Intrusive Granites in the Transvaal, the Orange Elver Colony, 

 and in SwazUand," by E. Jorissen : Trans. Geol. Soc. S.A., vol. vii, pt. iii, 

 pp. 151-60. 



'^ Proc. Geol. Soc. S.A., to accompany vol. viii of the Transactions, 1905, p. 32. 



' "Note on the Geological Position of the Basement Granite," by D. Dorffel: 

 Trans. Geol. Soc. S.A., vol. vi, pt. v, pp. 104-5. 



