In a note on Archæosigillaria Vanuxemi and Bothrodendron sp., published in the Geological Magazine for February last, Mr. J. W. Jackson speculated on the age of the beds at Meathop, in which these plant remains occur, and refers to the general classification of the Lower Carboniferous rocks of the Westmorland district, which I gave in this magazine in 1907. He remarks: “It is perhaps premature to attempt to fix definitely the exact horizon of these beds, as they appear to have been as yet but superficially studied.” Since the classification above referred to was published, I have devoted such time as could be spared from professional duties to an exhaustive examination of the whole northern area, the result of which has been to confirm the general conclusions already given in this magazine. In my forthcoming account of the district, I have given a detailed description of the Meathop section. The delay in publishing a full account of the northern area has been necessitated by the general structure of the district, which required a careful study of isolated outcrops, extending over a very large area, before an accurate co-ordination of the separate exposures could be established. If any justification for this delay were needed, it is supplied by Mr. Jackson's note, in which he confesses his inability to decide upon the age of the beds displayed in the isolated exposure at Meathop on the evidence afforded by the collections obtained during his visits to that locality.