She was referring to the Snowball quilt block which she said is from Virginia and "represents in a remarkably realistic fashion the flowering Snowball which blooms so profusely there in the early spring. It is a delight to the fastidious soul."
This is the second block she has named Snowball. The first was on February 2, 1933. There's a little more room between the curves of the first Snowball!
This Snowball block can be found in Electric Quilt's Blockbase program as #1518.
I almost didn't make this block because of the size. Each quarter of the block is only 3" finished which makes for a very small odd shaped template for the center of the block. I decided the block was really just a quarter square triangle block with curves in the corner so I started out with a quarter square triangle block like so-
On the right is the back of the block with the corners marked for cutting the curves. I am showing the quarter circle template used to mark the corners also. Notice that I have pressed the seams in opposite directions to make the center lay flatter.
The next photo shows the block with the corners sewn in- front and back. I'm showing the back so you can see how I pressed the seams.
To make a template for the curved background piece, draw a 4" circle and cut it into fours. The seam allowance is included so do not add any.
To make the template for cutting out the corners of the quarter square triangle blocks, draw a 3" circle and cut in fours. Make four of the units and sew together to make your 6" Snowball block.
Amy Bradley Designs.
There's a little bit of history in the post about this block. Notice that the drawing she shows from an old pattern book (1932) shows no space between the curves just like Nancy Cabot showed it!
There are some good examples of antique quilts at The Quilt Index here, here and here.