The alongshelf transport of volume, heat, salt, and nitrogen through a section across the continental shelf south of Nantucket Island was examined using moored current and bottom pressure measurements conjunction with data from 15 hydrographic cruises along the mooring transect. The mean ''observed'' transport of shelf water, estimated from the moored current observations in the traditional way for the Summer time period (March to September 1979), was westward at 38.9¿8.2¿104 m3 s-1. The ''geostrophic'' transport was inferred from differences between measured bottom pressures whose mean and trend were geostrophically levelled using the observed currents between each station. The mean geostrophic transports for the Summer and Annual (March 1979 to April 1980) time periods were westward at 31.9¿10.0¿104 m3 s-1, and 29.0¿9.1¿104 m3 s-1, respectively, with no significant seasonal variation. There was excellent agreement between the two methods in estimating transport fluctuations in the wind-driven (4--20 day) band. The best estimates of the mean advective transport of heat, salt, and dissolved inorganic nitrogen were westward 3.16¿1.42¿109 kcal s-1, 1.18¿0.53¿107 kg s-1, and 1.22¿3.03¿109 μg-at N s-1, respectively. Eddy transports were estimated where possible and found to be insignificant relative to advective transports in the alongshelf direction. This new value of mean salt transport is consistent with recently observed values of volume and salt transport into the Gulf of Maine through the Northeast Channel and the overall regional salt budget as computed by the Brown and Beardsley <1979> box model. The observed nitrogen transport can potentially supply between 39 and 53% of the nitrogen demand in the Middle Atlantic Bight. ¿ American Geophysical Union 1988