Choose a record, examine the returned list using BerkeleyMapper and "Related searches".
Records from the first of each month are likely to be special: many were generated by database errors (April 1901 being stored as April 1 1901).
Obviously, people sometimes collect at sites more than 60 miles apart on the same day. Even in the 1890's a collector could hop off a train at a whistle stop and botanize until the next train came along.
These entries are linked to a complete list of records for the collector and day. Use the sorting functions and BerkeleyMapper to find the source of the error. Note that the "Related searches" at the bottom of the detail display lets you search for records near a displayed record.