“Sitting on the Porch,” a postcard from ca. 1900, location and photographer unknown, via Miami University Libraries Commons on flickr.
(Click on the photo for a better look.)
The Bowden Postcard Collection of Miami University in Oxford, Ohio, holds over 480,000 postcards from nearly everywhere in the early 20th century world.
This image is not very seasonal, I must admit. Here in Stuttgart, we woke up this morning to a light covering of snow.
Children picking up our bones
Will never know that these were once
As quick as foxes on the hill. . .And least will guess that with our bones
We left much more, left what still is
The look of things, left what we feltAt what we saw. . . .
— Wallace Stevens, from “A Postcard from the Volcano“
enclos*ure 
I love using what is available to decorate the garden — in this case some logs and what looks to be shells. Beautiful!
I think you’re right — those are white shells. I thought they were rocks.