All students of Carboniferous geology will hail with pleasure Mr. W. Gunn's masterly paper in the August number of the GEOLOGICAL MAGAZINE (p. 342), and it is only to be regretted that the publication of such important stratigraphical facts should have been delayed for so long; but however useful from the numerous facts it contains, I must take exception to the deductions made from them. The paper is a remarkable one, because, while having for its object the correlation of rocks which occur over a wide expanse of country, no appeal has been made to palseontological evidence to clinch the author's views which are based on purely stratigraphical considerations.