Consortium "duplicates" mapping more than a half mile apart
One or more records called up by each of these links is questionable
Duplicates by definition come from the same location. Therefore, if putative duplicates are not mapping in the same spot, there is an error. The most common source of minor disjunction is that different people will assign different coordinates to the same place. Major disjunctions are more likely to be caused by a transcription fault or data entry error causing non-duplicates to be treated as duplicates.
Green: records mapping 1 or more degrees apart
Red: records mapping .1 or more degrees apart
Blue: records mapping .01 or more degrees apart (about a half mile)
Choose a record, examine the returned list using BerkeleyMapper and "Related searches".