Ontario Tax Assessment records - places indexed as England instead of Ontario
I found these pages where instead of Durham, Ontario, it was indexed as Durham, England.
I can't copy-paste the URL link in this box. Here is the collection title:
Canada, Ontario Tax Assessment Rolls, 1834-1899
For an example, see Mrs McLain in 1892 or Aaron Vollet in 1894
All those references would need to be corrected.
Also, it would be helpful to have a contact email where we could let you know when there are bulk errors in datasets, e.g. year indexed as 1884 instead of 1889 in marriage records for a whole district.