l which will extend therefrom and communicate to the bottom of the well bore although not an integrable part of the running tool rt or the hanger h but nevertheless a functional element in the cementing operation conducted subsequent to the setting of the hanger h and release of the running tool rt is a drill pipe cementing plug assembly 1000 fig7 j 21 23 and 24 which is pumped down the drill pipe dp and the interior a 3 of the running tool rt behind the cement slurry used to cement the liner l into the well bore and in front of drilling fluid or mud used to thereafter displace the cement from within the liner l the drill pipe cementing plug assembly 1000 has a longitudinally extending mandrel 1001 connected by threads 1003 at its lower end to a dropping plug 1002 extending therebelow immediately above the mandrel 1001 is a retainer element 1005 connected by threads 1004 to the sub 1001 the retainer element 1005 has a lowerly extending beveled end 1006 which houses a complimentary upwardly beveled end 1007 of an elastomeric wiper element 1008 longitudinally extending outwardly around the mandrel 1001 the wiper element 1008 is securely housed at its lowermost end by means of a circumferentially extending ring 1014 which engages the end 1013 of the plug element.