Necessary Causal Relation: E.g. square pegs do not fit into round holes in the same way round pegs fit - contingent causal relation: E.g. freezing water expands - (s) if it did not expand, it would still be water and still freezing - frozen. Not defined by volume, but by Microstructure.
Dispositional Properties/Place: are needed, because we speak about sentences with causal relations, not about their truthmakers - the dispositional statement provides the premise - the truth of a proposition depends on the situation as truthmaker, but truthmaker cannot simply consist in juxtaposition of cause and effect - otherwise, precisely the necessary connection that provides the counterfactual conditional would be omitted - the contingency refers to causal statements, not to relations between situations.