I found a Missouri Supreme Court case called Banks et al v. Galbraith et al.in my Google search. Here's the citation:
Reports of Cases Determined by the Supreme Court of the State of Missouri. Volume 149 By Missouri. Supreme Court 1898
It was a lawsuit filed by persons (of Indian tribes) alleging to be children of Banks, claiming entitlement to inheritance. Evidently by this court record William never married any of the Indian women with whom he allegedly sired children. The Indian litigants lost their case both at the original court level and on their appeal to the Supreme Court of Missouri. The court found that according to then current law in Missouri, Banks was never married to the mothers and therefore the children were not entitled to inheritance. The defendant named in the case is Galbraith because Catherine Galbraith was the executor of the estate.