We may pass next to the Sam Meylltern district, to examine the patch which Dr. Hicks on his sketch-map [Q.J.G.S. vol. xxxv. p. 297] has indicated as Dimetian with a strip of Arvonian along the north side. We read [l.c. p. 300], “Eastward (sic) of this, and as we approach the so-called altered Cambrian, rocks of a more felsitic character come in abruptly, and it is probable that these are of Arvonian age.” At the north end of the patch, by the Cromlech and Amwlch Lodge, the rock is however of the type which Dr. Hicks has termed Dimetian, and as it varies much in character at different parts of its course, I think we must ask for further proof that there is a second bed of rock of different age, in this area.