In his excellent paper on New Scottish Graptolites, published in the last monthly part of the GeologicalMagazine, Mr. John Hopkinson incidentally refers to the various opinions that have been held by different geologists concerning the thickness and geological age of the carbonaceous Graptolite-bearing shales of South Scotland. He expresses his conviction, derived from a study of the fossils they afford, that there is but “a single band of Graptolite shale, which runs through the Llandeilo beds of South Scotland, there being in this band several distinct zones, each marked by a different assemblage of fossils, but with many species in common.”