The Bala Volcanic Series of Caernarvonshire and Associated Rocks: Being the Sedgwick Prize Essay for 1888 is a geological book written by Alfred Harker. The book provides a comprehensive study of the Bala Volcanic Series, a group of volcanic rocks found in Caernarvonshire, Wales, and their associated rocks. Harker's research covers the geological history and characteristics of the rocks, including their mineral composition, texture, and structure...