| Site Name | Cockatoo Valley, Hollow Tree |
| Aboriginal or Torres Strait Islander Place Name | |
| Language Group, Nation or People | Oyster Bay |
| Present State/Territory | TAS |
| Colony/State/Territory at the time | VDL |
| Police District | Oatlands |
| Latitude | -42.532 |
| Longitude | 146.943 |
| Date | 23 Oct 1828 |
| Attack Time | Night |
| Victims | Aboriginal or Torres Strait Islander People |
| Victim Descriptions | Aboriginal |
| Victims Killed | 6 |
| Victims Killed Notes | |
| Attackers | Colonists |
| Attacker Descriptions | Stockkeeper(s) |
| Attackers Killed | 0 |
| Attackers Killed Notes | |
| Transport | Foot |
| Motive | Reprisal |
| Weapons Used | Firearm(s), Musket(s) |
| Narrative | In two separate attacks over two weeks in October 1828, near the northern and western shores of Lake Tiberias, 23 Oyster Bay warriors, possibly led by Tongerlongter, killed Anne Geary and Mrs Gough and two of her little girls and then Mrs Langford's son, John. On 23 October a reprisal party of 'stockkeepers and others', 'fell upon' the warriors' campsite near Cockatoo Valley at 11pm and fired after them, (HTC, Nov, 1, 1828) and 'killed and wounded a considerable number' (The Tasmanian, October 31, 1828). The killing of the two women, the little girls and the boy was the trigger for the proclamation of martial law on 5 November 1828. |
| Sources | The Tasmanian, October 31, 1828 https://trove.nla.gov.au/newspaper/page/25173660; HTC October 18http://nla.gov.au/nla.news-article4220434; November 1, 1828 https://trove.nla.gov.au/newspaper/page/641811; Ryan, 2012, pp 103-105. (Sources PDF) |
| Corroboration Rating | ** |
