A series of archaeological investigations took place in Upper Castle Park, Colchester from April 2014 to January 2015, in advance of and during works to improve the park amenities. These improvement works included changes to the children’s play areas and the Sensory Garden, the installation of interpretation panels, and the replacement of drains. <1> In April 2014, an archaeological watching brief took place during the installation of play equipment in a ‘sand play area’. This site is situated immediately to the north-east of the Park Café. It was formerly a crazy golf course, and occupies a slight dip in the park. Before the contractor’s groundworks started, CAT dug several small test pits by hand. The NGR for the sand play area is TL 9994 2548. The sand play area was designed to have a minimal impact on any surviving archaeological remains. Although the contractor’s groundworks were in general fairly shallow, several items of play equipment required footings deeper than 500mm below the existing ground level. This was the maximum construction depth stipulated in the Scheduled Ancient Monument consent. Therefore, four small test pits (T1-T4) were dug by hand by CAT staff on 15th April 2014 to examine the depth and extent of any archaeological remains in the affected locations. The test pits were all slightly different in shape and size, reflecting the outline of the proposed footings. They varied in depth from 700 to 900mm below the existing ground level. The creation of the sand play area involved extending the former crazy golf site by approximately 5m northwards over a grassed area. The final dimensions of the sand play area were thus approximately 38 m north-south by 15 m east-west. T4 was situated at the southern end of the area covered by the extension. A hedge and a fence between the two areas were removed. Following the excavation of the test pits, the contractors, Lightmain, proceeded with the groundwork. This was monitored by CAT staff during intermittent site visits. As well as extending the trenches in the locations of T1-T4, the contractors dug two short trenches adjacent to one another (T5 a & b), 600 mm deep, in the southern part of the site. These trenches were excavated using a mini-digger with a toothless trenching bucket, under the supervision of a CAT archaeologist, on 29th April 2014. Most of the contractor’s other holes were small in size and/or did not extend below the depth of the modern deposits on the site. As well as the installation of the play equipment, other tasks undertaken by the contractors included: the construction of footpaths; the installation of new raised borders, fences, seats and bins; and the raising raising of the general level of the site by up to 500 mm with the addition of a layer of sand. Sand play area The natural subsoil was not definitely reached in the sand play area. In the bottoms of T1 and T2, a brownish-yellow, slightly clayey deposit (L5) was uncovered, 750-800 mm below the modern ground level. A potsherd and a fragment of brick/tile, both of probable Roman date, were recovered from L5 in T1, and undiagnostic brick/tile fragments were observed in L5 in T2. Only a small part of L5 was excavated, so it was unclear whether it was an in situ Roman deposit. It was perhaps largely redeposited material, including some subsoil. Post-Roman topsoil or ‛dark earth’ In all of the test pits and the other trenches (T1-T5) in the sand play area, thick, dark greyish-brown deposits of post-Roman topsoil or ‘dark earth’ were encountered. These deposits were roughly 650-750mm thick. However, in places, slight stratigraphical differences were recognised within the ‘dark earth’, notably in T1-T3 (L2-L4). The lower 400-500mm of the ‘dark earth’ (L4) was fairly homogeneous in most of the trenches, although in T2 there were some brownish-yellow clayey mottles towards the bottom of L4. In T1 and T3, L4 was sealed by a more gravelly, dark greyish-brown layer (L3), approximately 200mm thick. The gravel was perhaps added in order to consolidate the ground. The upper 200mm or so of ‘dark earth’ in all the trenches was modern topsoil (L2). A quantity of residual Roman potsherds and brick/tile fragments was recovered from the ‘dark earth’. A clay pipe bowl fragment, of probable early 18th century date, came from just over half way down L4 in T2. Among the other post-Roman finds from L4 were some pegtile and slate fragments, as well as a small quantity of modern material from the upper part of L4. Peg-tile and slate fragments, and some modern finds were recovered from L2, and similar material was also observed in L3. Post-Roman ditch The thickness of the deposits of post-Roman topsoil or ‘dark earth’ in the sand play area contrasts with the relatively thin deposits a short distance to the east of the site. Here, significant Roman remains were found only about 300mm below the modern ground level (CAT Report 603, 3; <2>). The comparable Roman deposits in the sand play area were probably destroyed when a shallow post-Roman ditch (F3) was dug. This ditch was tentatively identified during previous archaeological work in this part of the Castle Park in 1983-4 (CAR 6, 372; <3>). It is also still visible as a slight dip extending north-south. The edges of the ditch F3 were not established in the sand play area, as they lay beyond the limits of the test pits and other trenches. The exact width of F3 is unclear, but was probably roughly 10-15m. The thick deposits of post-Roman topsoil or ‘dark earth’ in the sand play area probably accumulated as backfill in F3. The ditch, and the probable bank to the west, clearly formed a boundary of some antiquity. It is shown for example in a survey of the castle lands for Lord Stanhope in 1622 (Drury 1983, pl 41; <4>). Ditches are notoriously difficult to date, as they were often repeatedly cleaned out. Also, the backfill of the ditch could include the fills of later pits, the edges of which were difficult to identify. The find of the clay pipe bowl fragment from L4 suggested that the ditch had probably not fully silted up by the early 18th century. It is unclear whether F3 was originally part of the medieval outer bailey defences. Modern remains Parts of several modern footings were exposed in the sand play area, including north-south footings F1 in test pit T1 and F2 in T2. An east-west footing F4 was uncovered as the contractors extended test pit T3. The possible edge of another modern north-south footing was observed at the western end of T5a. These footings consisted of shallow concrete foundations, up to 600mm wide. They were reached between 250 and 400mm below the modern ground level, and were approximately 150 mm thick. Each concrete foundation supported a line of bricks, laid end-to-end. The bricks survived 1-2 courses high. The footings were sealed by modern topsoil (L2). They were probably the remains of structures associated with the former park nursery, such as greenhouses and/or cold frames. They are shown as such on OS maps dating to the 1960’s and 1970’s. A modern north-south water-pipe was uncovered at a depth of 400mm in T3. The existing modern gravel surface and associated make-up (L1) was 80-140mm thick. In T4, a layer of turf and topsoil (L6), approximately 150mm thick, sealed L1.