Funds for a light near Quantico, Virginia were appropriated in 1872. An engineering study recommended instead that lights be built  downstream, and an appropriation was made in 1874 to build a light on Port Tobacco Flats, with a day beacon for Mathias Point.
The passage describes the shifting priorities regarding lighting infrastructure in the area around Quantico, Virginia. Initially, funds were allocated for a light near Quantico but later shifted to build lights downstream and a day beacon at Mathias Point.