We have now catalogued the Columbus, Ohio 1:250,000 slope map from 1972. https://catalogue.nla.gov.au/Record/8054076 It is also digitised and can be viewed here (link will appear in catalogue tomorrow) http://nla.gov.au/nla.obj-1446462341/view Thanks for the lead to the USGS professional paper that describes it. Brendan Whyte National Libra of Australia