flow through the relatively large inner diameter of outer body 11 of first bottom cementing plug 10 inner mandrel 13 will fall through baffle adapter 40 onto a bypass baffle e g bypass baffle 500 illustrated in fig6 installed above the float valve or alternatively into perforated catcher tube 42 in either case longitudinal slots 17 in nose 15 of inner mandrel 13 assure that inner mandrel 13 does not substantially undesirably interfere with fluid flow the inclusion of a bypass baffle above the float valve protects the float valve and minimizes potentially high fluid turbulence at the interface between nose 15 of inner mandrel 13 and the top of the float valve assembly when operating personnel subsequently introduce a cement composition into the work string they also introduce a releasing device in certain exemplary embodiments the releasing device is a positive displacement releasing device such as a dart although other releasing devices such as a weighted ball may be used generally the releasing device is pumped down through the work string at the leading edge of the cement composition it then passes through top cementing plug 30 and lodges within inner bore 70 of inner mandrel 23 of second bottom cementing plug 20 thereby interrupting fluid flow next the differential pressure may be increased across seal 56 to a selected third differential pressure shearing frangible devices 52 and releasing second bottom cementing plug 20 from top cementing plug 30 in certain exemplary embodiments the differential pressure may be increased across seal 56 naturally by virtue of.