Rehnquist pointed out that Pennsylvania divides property interests into three categories. These categories are "the support estate, the surface estate, and the mineral estate." Each interest is deemed separate from the other and may have separate owners in fee simple.
Rehnquist's analysis of Pennsylvania law categorizes property interests into "the support estate," "the surface estate," and "the mineral estate." Each category is considered distinct and may have independent owners holding the interest in fee simple.