The full WA Museum report ( http://museum.wa.gov.au/maritime-archaeology-db/sites/default/files/ma_report_325_paula_bottle_message_020318_0.pdf http://museum.wa

The full WA Museum report ( http://museum.wa.gov.au/maritime-archaeology-db/sites/default/files/ma_report_325_paula_bottle_message_020318_0.pdf http://museum.wa.gov.au/maritime-archaeology-db/sites/defaul...) puts the longevity of the paper down to the bottle likely remaining buried in a layer of damp sand for most of the intervening time. Note that the bottle was found open, but half-filled with sand.