The data within this repository are observations from the North-South Rivers estuary and tidal marsh in the Massachusetts (USA) towns of Marshfield, Scituate, and Norwell. Types of data include 1) sediment core data, including x-ray fluorescence data, organic content, and foraminifera counts; 2) tidal channel observations of water level and turbidity; and 3) marsh platform observations of water level and turbidity.