In a characteristic article by Prof. Blake, “On the Base of the Sedimentary Series in England and Wales,” in the July Number of the Geological Magazine, amongst other erroneous statements, there is one which I must beg leave to correct. At page 310, in referring to the rocks of St. Davids, he makes the following statement: “While accepting the later petrological descriptions of Dr. Hicks, he (Dr. Geikie) minimized the separation between this [the Pebidian] and the Cambrian conglomerate, and challenged Dr. Hicks to prove his statement that the latter is chiefly composed of fragments of the rock on which it lies. This Dr. Hicks has never been able to do, seeing that the most marked feature of the conglomerate is that it is not composed of such fragments; instead of doing so, he now attempts to show that the matrix might have been derived from granitoid rocks.”