This paper pursues a question about the spatial relations between the three types of matter posited in Margaret Cavendish’s metaphysics. It examines the doctrine of complete blending and a distinctive argument against atomism, looking for grounds on which Cavendish can reject the existence of spatial regions composed of only one or two types of matter. It establishes, through that examination, that Cavendish operates with a causal conception of parts of nature and a dynamic notion of division. While the possibility of (...) unmixed spatial regions is found to be consistent with both the doctrine of complete blending and Cavendish’s anti-atomism by themselves, it is finally ruled out by a consideration of her theory of place. In fact, the geometrical question of the spatial relations between types of matter that drives the paper is ultimately exposed as illicitly mathematical from the perspective of Cavendish’s metaphysics. (shrink)