From the time of the appearance of Sedgwick's classic letters to Wordsworth, no volcanic area of Britain has probably been so well known in a general sense to the ordinary travelling public as the district of the English Lakes. Many geologists have since then visited the ground, and not a few of them have published additions to our knowledge respecting what is now known as the Borrowdale Volcanic Series. The most elaborate and detailed account of any part of it is that given by the late Mr. J. C. Ward in the _Geological Survey Memoirs_, wherein he embodied the results of his minute investigation and mapping of the northern portion of the district.[235] Notices of the petrography of some of the more interesting rocks have subsequently been published by Mr. Rutley, Professor Bonney, Mr. Harker, Mr. Marr, Mr. Hutchings and others. But up to the present time no complete memoir on the volcanic geology of the Lake District as a whole has appeared. The sheets of the Geological Survey map present a graphic view of the general distribution of the rocks, but so rapid has the progress of certain branches of geology been since these sheets were published, that the map is even now susceptible of considerable improvement. [Footnote 235: Sheet 101 S. E. of the Geological Survey of England and Wales and Explanation illustrating the same; and papers by him in _Quart. Journ. Geol. Soc._ vols. xxxi. xxxii. (1875-76). See also Messrs. Aveline and Hughes, _Mem. Geol. Survey_, Sheet 98 N.E. (Kendal, Sedbergh, etc.).]