As long as we're having a lens show again...

Well, depending on the source this one's either a first or third. In any event it was pretty darn big. I call it clamshell. Is that the same as bi-valve?

Prescott, Ontario Inner Light:

[img]http://albums.photopoint.com/j/View?u=39476&a=543312&p=11758171&Sequence=1&res=high[/img]

Here's a wee one at the Marine Museum in Kingston, Ontario:

[img]http://albums.photopoint.com/j/View?u=39476&a=543312&p=11758176&Sequence=1&res=high[/img]