Archaeological investigations in advance of and alongside construction work at Ronaldsway Airport, Malew, Isle of Man by Oxford Archaeology North in 2008-9 revealed several areas of activity, including a sub-circular hollow, approximately 7m in diameter, containing a ring of postholes, a hearth, and a north-facing entrance. On the basis of its morphology and date (several hazelnut fragments from inside the structure returned early eighth millennium dates), the feature has been interpreted as a Mesolithic pit house. Owing to its similarity and proximity to Cass ny Hawin, another previously discovered Mesolithic house on the Isle of Man, the Ronaldsway house has been named Cass ny Hawin II.

As with many of these house structures, Cass ny Hawin II produced abundant hazelnuts, including discrete dumps by the doorway, and very numerous lithic artefacts (approximately 30,000 were recovered from within the building). Such was the excellent preservation of the structure, traces of carbonised wood within its interior seem, from their arrangement, to be structural remnants, suggesting that the house was destroyed by fire. Given the importance of the house, and in order to investigate the spatial distribution of the flint artefacts and plant remains, its interior was 100% sampled by context and by spits within some 59 1m grid squares.

Several recent studies on hazelnut remains from Mesolithic houses, both in Britain and northern Europe, have highlighted the value of recording hazelnut abundance, alongside other features, as a means of identifying feature types and defined spaces within dwellings. Subsequently, all assemblages of hazelnut shell fragments from both the features and floor deposits of Cass ny Hawin II were quantified and weighed by an OA environmental specialist; a total of 10,238 hazelnut shell fragments were recovered from the site, producing a combined weight of 170.6g. A spatial plot of the data (above) suggests that although hazelnut shell was present throughout all contexts of the house, concentrations existed. Specifically, several lie at the perimeter of the house, flanking its entrance, which have been interpreted as hazelnut caches. Higher concentrations occurred towards the centre of the house, which is interpreted as reflecting the main food preparation/cooking area inside the hut. These were associated with features, interpreted as either roasting or waste pits, and a putative willow basket.