Clickable map showing JPEG scans of the 1:100,000 scale geology series for entire country of Peru. These JPEG files are barely legible, but they are useful because they are one complete scan and they can easily be georeferenced in to a GIS. If you own the paper copy of a given map (for reading the fine print) then combined with these JPEGs you can georeference and digitize cartographic and geologic features from throughout the country.
Despite the blocker, Firefox allows you to save out the JPG files.
Note: the grid system in these maps is PSAD 1956 (La Canoa) not WGS84. See this post concerning georeferencing and reprojecting of these scanned maps.