the date 15?4 carved into a stone. McIntyre hypothesized the crew of a Portuguese caravel may have built a stone blockhouse and defensive wall while wintering on a voyage of discovery down Australia's east coast. Since McIntyre advanced his theory in 1977, significant research on the site has been conducted by Michael Pearson, former Historian for the NSW Parks and Wildlife Service. Pearson identified the Bittangabee Bay ruins as having been built as a store house by the Imlay brothers, early European inhabitants, who had whaling and pastoral interests in the Eden area. The local Protector of Aborigines, George Augustus Robinson, wrote about the commencement of the building in July 1844. The building was left unfinished at the time of the death of two of the three brothers in 1846 and 1847. Other visitors and writers, including Lawrence Fitzgerald, have been unable to find the 15?4 date. Writing in Beyond Capricorn in 2007, Peter Trickett suggests the date McIntyre saw may be random pick marks in the stonework. Trickett accepts Pearson's work, but hypothesizes that the Imlays may have started their building on top of a ruined Portuguese structure, thus explaining the surrounding rocks and partly dressed stones. Trickett also suggests the Indigenous Australian name for the area may have Portuguese origins. Kilwa Sultanate coins In 1944, nine coins were found on Marchinbar Island by RAAF radar operator Maurie Isenberg. Four coins were identified as Dutch duits dating from 1690 to the 1780s, while five with Arabic inscriptions were identified as being from the Kilwa Sultanate of east Africa. The coins are now held by the Powerhouse Museum, Sydney. In 2018 another coin, also thought to be from Kilwa, was found on a beach on Elcho Island, another of the Wessel Islands, by archaeologist and member of the Past Masters group, Mike Hermes. Hermes speculated that this may indicate trade between indigenous Australians and Kilwa, or that they coins had arrived as a result of Makassan contact with Australia. Ian S McIntosh's view is also that the coins were "probably introduced by sailors from Makassar... in the first wave of trepanging and exploration in the 1780s." Criticisms and alternative views of the Dieppe Maps Possibly because of the degree of conjecture involved in the theory of Portuguese discovery of Australia, there have been a number of critics. Matthew Flinders cast a sceptical eye over the "Great Java" of the Dieppe