De Saint Aloüarn


In 18th Century France, there was a widespread belief in a vast southern land, often referred to as Gonneville Land. This continent was considered to be distinct from New Holland, the position of which was only roughly known and marked on the charts of the day. Even after James Cook returned from the Pacific in 1770, the identification of this land remained one of the most important discoveries still to be made.

During an interlude of peace following the Seven Years' War, the French Government decided to support an expedition which would hopefully equal Cook's achievements, solve the mystery of the Utopian land filled with gold and other riches and restore the prestige of the French navy following defeats during the war.

In 1771, a young, ambitious naval officer and Breton noble, Yves-Joseph de Kerguelen-Trémarec, was given permission by the King of France, Louis XV, to undertake a voyage of exploration to the Southern Ocean with the aim of discovering the Terres Australes. His second-in-command was fellow Breton Louis François Marie Aleno de Saint Aloüarn.

Bad weather and poor rigging led de Kerguelen and de Saint Aloüarn's ships to become separated. In command of Gros Ventre, de Saint Aloüarn managed to round Cape Leeuwin and sailed north.

On the evening of 29th March 1772, the ship entered Shark Bay and anchored in Turtle Bay and the following day de Saint Aloüarn sent the ship's boat (pinnace) ashore with officer Mengaud de la Hage, the boat's crew and five soldiers to reconnoitre the land and claim possession. After walking about three leagues (lieues) (12km) inland, finding little evidence of human occupation, they returned to the coast and took possession of the land.

Prise de Possession took place on the northern cliff of Dirk Hartog Island, overlooking La Baie des Tortues (Turtle Bay). The annexation was commemorated by raising a flag, firing a volley of rifle shots and reading a prepared document written in the usual terms in such circumstances. It was then inserted into a bottle which was buried at the foot of a small shrub or tree. Near it they placed deux écus de six francs (two six franc coins).

On 8th April, Gros Ventre left Shark Bay and headed for Timor arriving on 3rd May 1772, with many of the crew sick. As he was unable to get the necessary provisions in Dili, de Saint Aloüarn left on 1st July for Batavia to get them there and then make the journey back to Ile de France (Mauritius). He managed to supply the ship and set sail for Mauritius on 8th August, but by then both he and Mengaud de la Hage were sick from fevers contracted in Batavia.

Early September Gros Ventre finally arrived back in Mauritius, but de Saint Aloüarn was ailing fast and died on 27th October 1772 in Port Louis, Ile de France (Mauritius), his 34th birthday celebrated just a few weeks earlier as he sailed through the Sunda Strait.

Map depicting features of Dirt Hartog Island

Detail from the de Rosily chart of April 1772
Image copyright WA Museum

Detail from the de Rosily chart of April 1772, showing Turtle Bay at the north end of Dirk Hartog Island, de St Aloüarn's anchorage, the boat soundings, and the annexation site. The 'A' inland is believed to mark the furthest point travelled inland. Map superimposed on a georeferenced aerial photograph of the north end of the island.


In January 1998, an expedition led by M. Philippe Godard and including members of the Batavia Coast Maritime Heritage Group from Geraldton, discovered a French écu bearing the head of King Louis XV and dated 1766 at a site on the cliff top overlooking Turtle Bay. The silver coin, which was encased in a lead capsule, is believed to be associated with de Saint Aloüarn's expedition. An initial evaluation by the WA Museum of both the artefact and the site concluded that it was a genuine find.

1998 WA Museum Expedition

The site was considered to be at risk from natural erosion but more significantly from further uncontrolled explorations. This was a risk exacerbated by the broad media coverage that accompanied the discovery of the coin. In collaboration with the Centre for Archaeology at the University of Western Australia, the Western Australian Museum fielded an archaeological expedition to the site in March - April 1998. The project had the broad aims of assessing and recording the site and exploring undefined locations along the ridge above Turtle Bay.

Front and back view of an 18th century coin

The écu (or louis d'argent) dated 1766 found by the Goddard Expedition
Image copyright WA Museum

The expedition consisted of three activities:

  • a visual surface survey of the ridge above or Turtle Bay
  • a metal detector survey of the land around the 'coin tree'
  • test excavations, again in proximity to the 'coin tree'

The visual survey noted low density scatters of later 19th and 20th Century artefacts and remnants of campfires, in association with the railway. The survey also noted the area was littered with evidence of several excavations.

The metal detector survey involved a detailed survey of a 13mx17m area around the 'coin tree' and a broader prospective survey of ground further afield. The survey noted a clear concentration of detected targets within a 10m radius of the 'coin tree'. All of the targets that were excavated were found in the upper strata. It was therefore concluded that the concentration was a product of erosion collecting the artefacts at the head of the gully and led the expedition to 'generally ignore the metal detecting survey in deciding on the placement of controlled test excavations'.

Test excavation involved detailed hand excavation of four small test trenches in the vicinity of the 'coin tree'.

Three scientists posing near an excavation site

Excavated Bottle In-Situ: The bottle in-situ. The 'coin tree' is visible behind the finders
Image copyright WA Museum

The expedition uncovered a French wine bottle, sealed with lead encapsulating another French écu dated 1767. It was clear that this find and the Godard coin were part of the de Saint Aloüarn annexation assemblage. Unfortunately, the parchment annexation document was not found inside the bottle. The WA Museum expedition was limited in time and resources, and was only ever intended to be an initial evaluation of the site. So, while a significant artefact was discovered, the context in which it was found was not determined.

Bottle recovered from a shipwreck

The bottle and capsule, before being opened
Image copyright WA Museum

2006 WA Museum Expedition

One of the major aims of the 2006 archaeological project was to re-examine the annexation site and recover additional evidence of the French landing, specifically the so-called parchment bottle, which was possibly the last remaining component of the annexation artefacts.

Six trenches totalling approximately 60m² were excavated over six days and a detailed metal detection survey took place. The archaeological excavations and initial inspection of artefacts resulted in the conclusion that the first coin and cap found were not in their original location, but had probably been discarded by a fossicker and the bottle they had once sealed (and possibly the annexation papers) had long since gone. The bottle, found by the Museum team in 1998 had clearly been buried in this place by the French explorers.

Archaeological remains associated with the construction and maintenance of the railway and Cape Inscription lighthouse are now considered part of a larger site. This includes remains of the jetty submerged in Turtle Bay, the railway and winding shed and the lighthouse site.

Line rail link down a jetty

The light rail jetty, with the builders' camp
Image copyright WA Museum