This week I am in Canada. Yesterday morning on our way to Niagara Falls thru New York, we stopped at the northern shore of Skaneateles Lake for a short walk along the lake and on the pier that extends into it.
These operculated snails were abundant on the shore.
I suspect they are a non-native species of apple snail (family Ampullariidae). A more definite identification will hopefully follow after I've had a chance to send their pictures to more knowledgeable people.