Della and Rick,
The markings can either be solid as brushmarks, or loose which appear as lines or elongated spots.
Rick, I noticed (checking back to your original post) that you used Sweet Surrender for these seedlings. I have noticed that it does tend to give mostly seedlings with lines when crossed with various brushmarked lilies. I use Sweet Surrender in some of the crosses for the higher bud count, and the pastel white that first opens as a very pale yellow with greenish center tints. I do get some interesting seedlings from it.
4th pic in the 2nd row is from Sweet Surrender x bsmk sdlg.