A total of five trenches were excavated at the First Time Sewerage Scheme at Mountfield, East Sussex. These were targeted over anomalies identified in the earlier geophysical survey. Trench 1 was situated in the north of the site (Area 2) and the remainder were excavated in the south adjacent to the River Line. A single trench to the south of the river could not be excavated for logistical reasons. The geological substrate was encountered at a maximum height of 45.96m AOD in the north of the site and 32.99m in the south. Sondages dug in the southern ends of Trenches 3 and 5 revealed solid sandstone geology at 29.92m and 28.54m respectively. Samples taken from deposits noted in the sondage in Trench 4 contained modern rootlets and plant material and a relatively low percentage of charred macrofossils. Early activity at or near the site was evidenced by a single Mesolithic flint core recovered from the topsoil of Trench 3. Two shallow ditches were recorded in Trenches 2 and 3. The feature in Trench 2 contained Post-Medieval building tile whilst the feature in Trench 3 failed to produce any dating evidence.