New Zealand Archaeological Association Site Record Number Y17/270 is a pit/terrace site that forms part of the dense archaeological landscape of the Tolaga Bay (Uawa) area. It is located on Mangaheia Station, to the west of the Tolaga Bay township.

Pit sites and the many other recorded archaeological sites including pa, midden, gardens and urupa reflect the intensive Maori occupation of the Tolaga Bay from the time of initial Polynesian settlement approximately 700 years ago. Access to abundant food resources from the sea, rivers, inland forests and horticultural production (kumara) meant that a large population could be sustained. It has been estimated that the early Maori population of Tolaga Bay totalled approximately 1200; and the main iwi was Te Aitanga a Hauiti.

Pit and pit/ terrace sites are very common in Tolaga Bay, and demonstrate the importance of horticulture to Tolaga Bay's earliest inhabitants. The Bay's fertile soils and temperate climate were well suited to kumara gardening, and the pits were used for storing harvested kumara over the winter months. Rectangular storage pits (which were once roofed with a layer of earth), are more prevalent than the underground storage pits found elsewhere in New Zealand, a pattern attributed to the harder substrate of the soil in this area. They are in fact the most common archaeological site type in Tolaga Bay, and are found along the river banks and on the rolling hills to the south of the Bay. They are generally located in clusters on knolls or terraces, as with this site -Y17/270, or on ridge crests, in lines from end to end. Terraces are discrete areas that were deliberately levelled by Maori to create a flat surface for activities or buildings.

Pit/ terrace site Y17/270 is located under pasture on a knoll to the south of the Waiotahota Stream, approximately 700 metres west of the end of Mangaheia Road, where the station buildings area. Several other pit and pit/terraces sites are located in the surrounding area, and two pa are located on the ridgeline directly to the south (Y17/145 and Y17/146).

This site was first recorded by R. Sheppard for the New Zealand Historic Places Trust in 1982, presumably as part of the archaeological survey work undertaken by archaeologist Kevin Jones in the Whangara, Tolaga Bay and Uawa Catchment areas in 1982-1983. This survey work was undertaken to gain information about the nature of prehistoric settlement in this locality, and also to evaluate specific sites for registration under the Historic Places Act 1980. Sheppard recorded a total of five raised rim pits along the knoll, measuring from 1.5 metres x 1 metre x 0.2 metres (depth) to 4 metres x 1.5 metres x 0.6 metres (depth). He also recorded a terrace measuring 3 metres x 2 metres. Three of the five pits (labelled 'Features A -C') were located towards the northern end of the knoll, and lay on a north-south alignment, whilst the remaining two pits were located some distance to the south. Feature F lay on a north-south alignment approximately 60 metres south of the terrace (Feature D) whilst Feature E was located approximately eight metres to the southwest from Feature F, and lay on an east-west alignment. With regards to site condition, Sheppard noted that the pits and terrace were located in an area of slumping, which could pose a future threat to the site.

Pit/terrace site Y17/270 was revisited by archaeologist Bridget Mosley in 2000 as part of the New Zealand Archaeological Association Site Recording Scheme Upgrade Project. Mosley relocated the site and concluded that it was in average condition, and under ongoing threat from stock damage and slumping. A New Zealand Historic Places Trust site visit in November 2007 revealed no major changes to the site. The pits and terrace were still clearly visible, and in average - good condition.

Y17/270 is one of numerous pit and pit/terrace sites recorded in the Tolaga Bay area. It is part of a dense archaeological and cultural landscape that is of considerable significance to Te Aitanga a Hauiti, reflecting the intensive Maori occupation and settlement of the Tolaga Bay area since the 14th - 15th centuries AD, and the important role that horticulture played in this.