Direct subordination also occurs in GP's, ie. phrases such as "the boy's book" or "ladies' shoes". These are curious structures which derive from the Old English case system:
OE:
nominative stan
accusative stan
genitive stanes
dative stane
NE:
stone's
GP's can be paraphrased by PP's:
If subordination was not indicated, the phrase would not clearly be possessive; (16d) could mean "a book for boys", as in "The Boys Own Annual".