I spent part of my last full day in Montreal photographing and filming the snails I found in my sister's garden. One of them was the following.
The diameter of the shell was 8.7 mm. Note the hairs visible along the edge of the body whorl. Based on the descriptions in Identifying Land Snails and Slugs in Canada – Introduced Species and Native Genera, I have identified this specimen as Trochulus hispidus (the other candidate is T. striolatus). It is a native of Europe that has been introduced to Canada.