It's a rolled up bundle of (probably 40) strips of batiks, 2.5" wide x 44" long. You know how Moda came up with their "Bake Shop" concept for marketing pre-cuts? And they coined the term "jelly roll" for these (and turnovers, and layer cakes for different pre-cut shapes and sizes). But of course they have trademarked their names. So "Sushi Rolls" is what Princess Mirah Batiks (Bali Fabrics) calls their same type of product.
http://www.bali-fabrics.com/shop/196-s
I think "jelly roll" has entered the quilting dictionary the same way that "Kleenex" has come to mean tissue.