Excerpt from The Bala Volcanic Series of Caernarvonshire and Associated Rocks: Being the Sedgwick Prize Essay for 1888 Introductory: Three divisions of the county, 1; specimens, 3; litera ture, 3. Rhyolitic lavas: Groups of ows in eastern Caernarvonshire, 8; Lleyn rhyolites, 10; the Welsh felstones true lavas, 12; chemical composition, 13 characters in the field and in hand-specimens, 16; microscopical study, 18; ashes and agglomerates, 25. Nodular rhyolites: Wide distribution, 28; general characters, 29; discussion of theories, 30; description of specimens, 35. The acid intrusives: Distribution of the rocks, 41; chemical composi tion, 46; characters in hand-specimens, 47; microscopical study, 48; riebeckite, 50; types of micro structure in the rocks, 53; 'con cretionary patches, ' 57; granite of Sam, 58. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works."