Here's another picture with sunlight.

Montauk daisy?

My first thought was Montauk daisy as well.

Dee

I thought it might have been one of the saxifrages - S.urbium?

What would be the difference in Montauk daisy and a Shasta Daisy?

as far as I can see, it is the leaves. Shasta daisies have tall slim leaves and are not shiny. This plant has shiny leaves and they're scalloped (for lack of a better word to describe them) - but I'm no expert or I would have known from the get-go what this plant was. :)

My montauk daisy has thick sort of rubbery leaves and blooms very late--October maybe. I just went out and checked--The leaves are shaped much like yours, not rubbery as I thought.
Mine were in pots, this is second year in ground and the bunches of leaves are at the end of 12-15 inch stems. No buds yet.

Mine is only maybe 6-7" tall. I was thinking of putting it in a big planter I have. But thinking I should wait till early Spring? I doubt we'll get any flowers this Fall but you never know. They may show up in October. Being it is so small, I'm thinking it won't bloom.

Montauk daisy - Nipponanthemum nipponicum - thrives in sandy conditions, not surprisingly near the shore. It does have rubbery foliage and blooms late--in October where I am. Yes, it's in the daisy family but as far as I'm aware it's not a Shasta daisy that blooms mid-summer.

It's quite a woody plant that should be pruned in spring (since it blooms in the fall) to control height/size. I grew my plants from seed via winter sowing but have so far not been overly impressed with their performance in the perennial garden beds. It's definitely a low/no-care perennial aside from pruning to control size/shape.