Letter to Sir Archibald Geikie from George James Allman, 28 December 1861

Letter to Sir Archibald Geikie from George James Allman asking permission to make a copy, for his classroom, of a large unpublished map which Geikie has sent him. He discusses the contents of the map. He asks for clarification concerning the differences in rock types indicated between this map and a previous sketch map which is in his possession.