An experimental investigation has been carried out on the penetrative natural convection flow and thermal transport resulting from an isothermal vertical surface immersed in a stably stratified, two-layer, ambient medium, in which an essentially isothermal heated layer overlies a relatively cooler isothermal layer of the same fluid. Measurements of the thermal field are carried out for several surface temperatures and the corresponding isotherms obtained. The surface temperature is taken as lower than the upper layer temperature so that a downward natural convection flow is generated adjacent to the surface in the upper zone and the penetration of this flow into the lower region is investigated. Velocity and temperature profiles are measured to determine the mass flow rates across the interface between the two regions. The local heat transfer rates are also measured at various locations on the isothermal plate. For the surface temperature lying between the upper and lower layer temperatures, an upward flow is generated in the lower region and a downward flow in the upper region. The two Rows collide near the interface, giving rise to transport across the interface.