This tiny thumbnail is all the American Geographical Society Library will let you download from their digital map collection, but if you click on the photo you’ll be routed to the University of Wisconsin’s Milwaukee Libraries Digital Collections page and have access to the map in stupendously high resolution, with the capability to zoom in and move around Þorvaldur* Thoroddsen’s 1901 Geological Map of Iceland; Surveyed in the years 1881-1898. This version was published in English at Copenhagen, but I have featured the 1906 version before, and keep a printed copy of the later publication (publ. Gotha, Germany), hanging in my room in Ithaca.
I use my copy for any quick reference I need to make while reading or thinking about places in Iceland for my research, and I also plan on starting to use little ball pins to mark down the most often-traveled areas and more quickly become accustomed with place-names and distances between locations. One interesting difference between the 1901 English and 1906 German versions of this map is the Vatna/Klofa Jökull region, which in the latter includes Mt Paul and Vatna Jökull Housie, both named by William Watts during his expeditions. The 1906 edition also has actual topographic elevation lines for the jökull area, while the lines around the 1901 jökull region are there merely to show it is glacial. I’m not sure why these differences exist, since by 1901 Watts’ landmarks were well known; I assume it has more to do with the different men who drew and published the maps in Denmark and Germany than with Thoroddsen himself.
* The symbol [Þ] in Þorvaldur, which is called ‘thorn,’ is now only in use by the Icelandic alphabet, but was once seen in Old English as well. It is pronounced like the ‘th‘ in “thick.” The lower-case form is [þ]. In case you’re curious, another common Icelandic character [Ð / ð], called ‘eth,’ was also in Old English and is pronounced like the ‘th‘ in “the.”