River Darent
North of Dartford the Darent is tidal and , just before entering the Thames , receives the waters of the River Cray at Dartford & Crayford Marshes where the rivers form administrative boundaries between Greater London and Kent , ( specifically , the London Borough of Bexley and the Kentish borough of Dartford ) . 
<triplet> Greater London <subj> Kent <obj> shares border with <subj> London Borough of Bexley <obj> contains administrative territorial entity <triplet> Kent <subj> Greater London <obj> shares border with