III.—On the Homotaxial Equivalents of the Lower Culm of North Devon

Extract

I am glad that my paper on the Coddon Hill beds, published in the Geological Magazine, August, 1904, pp. 392–403, has aroused criticism, and could only have wished that Dr. Vaughan had been familiar with the Carboniferous sequence of the Pennine area and Belgium. The matter is not one to be solved by the casual appearance in any definite bed of a few Brachiopods, at one only of the many horizons at which they are known to occur in other localities, for the whole of the fossils, which are quoted by Dr. Vaughan as the foundation for his argument that the Coddon Hill Beds are low down in the Carboniferous sequence, are equivocal as far as their value as zone indices goes. And on the other hand, Dr. Vaughan completely ignores those fossils which are unequivocal and which denote a well-recognised horizon, and curiously enough, too, correspond with a marked change in lithological character of the Carboniferous sequence. In the first place, I do not see where Dr. Vaughan found any statement in Mr. Howe's and my paper on the Pendleside group at Pendle Hill (Q. J. G. S., vol. lvii) that the Pendleside series are the equivalents of the Millstone Grit of South Wales and the Mendip areas. The table on the page quoted (p. 388) distinctly shows that we consider the Pendleside series to lie universally below beds equivalent to Millstone Grit, and we do not mention the series of the Bristol and Mendip area because we were not well enough acquainted with that district to do so.