Note 221 — Chapter XIII · THE ERUPTIONS OF LLANDEILO AND BALA AGE
Reading edition
See Sheet 74 of the one-inch map; Sheets 32, 35, 37 and 38 of the Horizontal Sections; and chapter xxxi. of the Memoir on the Geology of North Wales.
Reading edition
See Sheet 74 of the one-inch map; Sheets 32, 35, 37 and 38 of the Horizontal Sections; and chapter xxxi. of the Memoir on the Geology of North Wales.