18 points
Could be cool but who knows without a key to read it.
3 points
5 points
Is there a key?
2 points
*
- Map key (and split map copy): “Back Matter” PDF (19 MB) from the map + article at geoscienceworld.org
- Text explanation in article without map at USGS.gov (see page 7 of 28)
Unfortunately, I cannot find a non-rasterized digital version even though the original clearly was a digitally typeset document.
