Summary
1887-Jan through Mar: Elizabeth was born to Joseph Coles & Elizabeth Bryant. Her birth was registered sometime during those months in Bicester, Oxfordshire, England. Her mother's death was registered during the same time period and place.
1887-Feb-06: Elizabeth was baptized in Stratton Audley, Oxfordshire, England.
1891-Apr-05: England Census with father & 3 siblings at Stratton Audley, Oxfordshire, England.
1901-Mar-31: England Census at The Aston Training School, Aston, Oxfordshire, England.
1911-Apr-03: England Census was a Scullery Maid at the Harrow School (a boys boarding school), in Harrow on the Hill, Middlesex, England.
1918-Jan-28: Elizabeth married WW1 soldier Donald Robert Robertson, Jr. in Bicester, Oxfordshire, England.
1918-Mar-11: Elizabeth was living at 55 Sheep Street, Bicester, Oxfordshire, England, according to her husband's military records.
1918-Aug-01: Elizabeth was living at "Glanderbot", Salisbury Road, Seaford, Sussex, England, according to her husband's military records.
1919-Mar-23: Elizabeth was living at 3 Springfield Road, Greenhill, Harrow on the Hill, Middlesex, England, according to her husband's military records.
1919: Elizabeth arrived in Canada.
1921-Jun-01: Canada Census with husband and his two daughters at Lot 3, Block 9, Empress, Alberta, Canada.
1921-Aug-15: Son Donald L was born, then died the next day, Empress, Alberta, Canada.
About 1924: Son Leslie R was born, Empress, Alberta, Canada.
1925-Jan-27: Son Gordon Allan was born, Empress, Alberta, Canada.
1925-Jun-24: Husband Donald died at Empress, Alberta, Canada.
1926-Jun-01: Canada Census with her two stepdaughters and two sons in Empress, Alberta, Canada.
1931-Jun-01: Canada Census with her two sons in Empress, Alberta, Canada.
1932-Dec-09: Elizabeth and her sons Leslie & Gordon went to England.
1933-Mar-25: Elizabeth and her sons Leslie & Gordon arrived back at Halifax, Nova Scotia on the ship "Montcalm", from Liverpool, England.
1935, 1940, 1945: Canada Voters Lists in Empress, Alberta, Canada.
Thereafter, she disappears from the records. Presumably she remarried and moved away.
1977-Apr-03: Some people on the Ancestry website say she died on this day in Calgary, Alberta, Canada, but none of them cite any sources for that information.