sentences:  In 1818, the British brig , captained by Lieutenant Ritchie, encountered the true Tryal Rocks.They were not recognised as such, however, as the Tryal Rocks were then thought not to exist, and they had previously been thought to be well to the west of Ritchie's reef.In 1920, Ritchie's discovery was published as "Ritchie's Reef"; it was also sometimes referred to as "the Greyhound's Shoal".