Vintage John H. Martin Hand Colored Map of Nantucket “Geological Base” Consign Now DeptNantucket ArtSizeOverall 22 in. x 32 in. Vintage John H. Martin Hand Colored Map of Nantucket “Geological Base”, color key showing the different geological base types and locations of each on the island, by John H. Martin, Harvard University. Overall 22 in. x 32 in. Please note that this auction has ended. Click here for an overview of this auction.