Physiography of N. Britain in Millstone Grit Times. 133 



Harrogate area (Geology of Harrogate, 2nd 

 Edition, p. 5). 

 {d) The Cayton Gill beds are most calcareous in the 

 easternmost exposures, as at Fountains and 

 Tanfield. 

 {e) In the south of Yorkshire, near Shefheld, the 

 Grits become so much finer in grain eastward as 

 to resemble Coal Measures. (See Geol. Surv. 

 Mem., Yorkshire Coalfield, pp. 38, 39, 45, 

 46, 47, and Plate 2, Figs, i and ia). 

 It is difficult to explain this attenuation and finer grain 

 eastward on the hypothesis that the source of the material 

 of the Grits lay in that direction. The clear water fauna of 

 the Cayton Gill band in the north-east corner of the Grit 

 outcrop also seems similarly against such an hypothesis. 

 Dr. Gilligan points out : — 



(i) The resemblance of the Torridonian of Scotland, 

 the Millstone Grits of the North of England, 

 and the Sparagmite of Scandinavia. 



(2) He states {op. cit. p. 286) that the Sparagmite was 



in all probability derived from the same source 

 as the Torridonian. 



(3) The Torridonian is believed to have been derived 



mainly from the north-west [i.e. from a land 

 lying off the N.W. of Scotland] and in this 

 Dr. Gilligan concurs {op. cit. p. 286). 



If the Sparagmite or Torridonian both came from a land 

 area to the N.W. of Scotland and are both closely allied to 

 the Millstone Grit, it is difficult to understand why it should 

 be necessary to assume that the Millstone Grits were derived 

 mainly from a different source, as is suggested by Dr. Gilligan 's 

 map. 



P.S. — Since writing the above notes, a short article 

 has appeared in The Yorkshire Post {' The Lost Atlantis,' 

 •3rd December, 1920) which reports Dr. Gilligan as stating 

 that he has recently received rock samples from Newfoundland 

 ' absolutely identical with the Millstone Grit, and the material 

 of the rock, in several ways peculiar, was obviously from the 

 same source as that of the English rock.' 



This most important evidence throws further weight in 

 favour of a north western as against a north eastern origin 

 for our Grits, and is in line with the occurrence of rocks of 

 Scandinavian type in Rockall, the similarity of the faunas 

 of the Nebraskan Coal Measures and Scotch Millstone Grit, 

 and the evidence adduced above. 



Against this theory the only evidence of any weight 

 appears to be the difficulty of a river passing over the mid- 

 Scottish trough (Hind, MS.) and the occurrence in the grits 



liai April 1 



