I received an e-mail today from one of my mother's cousins, informing us of the death of my grandaunt, Bertha Wilma (VALK) MEYERING KRAMER. She was the eldest child of the marriage of my maternal great-grandfather, William James VALK, and his second wife, Ida Eva (LAMBRECHT) SCHADLER. The widowed William and Ida brought a total of eight children to their marriage (seven were his [one other died in infancy], one was hers), and then proceeded to have eight more children, five of whom survived infancy. Bertha's death leaves only two children remaining of this household: Ida's son from her first marriage, and their youngest daughter.
I don't ever remember meeting Aunt Bertha, who was my maternal grandfather's younger half-sister, although it's possible I may have met her as an infant or very young child on one of our frequent visits to Michigan from Alaska. Bertha's obituary can be found online at the Grand Rapids (Michigan) Press.
Update: I've analyzed Bertha's obituary here, sharing the discoveries I made.