Hello, I was born Susan Bishop & my mother was a Slemon, her father Leo Rex Slemon (known as Rex), born 1903 in Ottawa, his father Edward Trewin Slemon, 3rd of 4 sons of: William Slemon (son of Richard Sleeman) and Joanna nee Trewin. Thank you for confirming that ancestry of Joanna (Trewin) Slemon; I thought I had it but was not sure. I've been on Ancestry.ca about a year; I have found the 1861, 1871, and 1881 censuses for the Slemon's, but it was spelt "Slimon" in 1861, Slemen in 1871, & settled to Slemon in 1881. I mention this because there was a William Trewin age 13 living with them in 1861 (? A cousin of Joanna?, I thought possibly an orphan). There was A dentist, born a few years earlier than my grandfather "Dr. Garnet Trewin", we called him uncle, but probably a cousin of my grandfather. That connection, & the identity of young William on the census are my dilemmas. Your search for Trewins may be also hampered by the census-takers' spelling, handwriting, and transcription of such, being an unusual name, I have a marriage record where Trewin was taken for "Lewin", so try that.