<Tr> <Td> September 26, 1907 </Td> <Td> The Newfoundland Colony became a dominion of the United Kingdom, inheriting the Labrador boundary dispute . </Td> <Td> Disputes: </Td> </Tr> <Tr> <Td> April 11, 1908 </Td> <Td> A boundary treaty redefined the maritime border with the United States . Among other changes, this "de-enclaved" Horseshoe Reef in Lake Erie by making the water around it contiguous with the water on the American side of the border . </Td> <Td> no change to map </Td> </Tr> <Tr> <Td> August 20, 1910 </Td> <Td> A boundary treaty with the United States addressed a slight uncertainty in the maritime border in Passamaquoddy Bay between New Brunswick and the United States . The border was adjusted to run east of Pope's Folly Island, which previously lay on the border line, and had been the subject of some debate for many years . </Td> <Td> </Td> </Tr> <Tr> <Td> May 15, 1912 </Td> <Td> Manitoba, Ontario, and Quebec (act) were all expanded northward into land from the Northwest Territories . Quebec was expanded north to fill the mainland, Manitoba extended north to the 60th parallel north, and the new border between Manitoba and Ontario ran northeast from the previous northeastern corner of Manitoba . </Td> <Td> </Td> </Tr>

What might have caused changes to the map of canada