Chapter 2
On some New Trilobites from the Upper Cambrian Rocks of North Wales, Geological Magazine volume 4 1867 pages 294-295. On the "Lingula Flags" or "Festiniog Group" are the Dolgelly District, Geological Magazine
On some New Trilobites from the Upper Cambrian Rocks of North Wales, Geological Magazine volume 4 1867 pages 294-295. On the "Lingula Flags" or "Festiniog Group" are the Dolgelly District, Geological Magazine