The reef, with a red beacon on top, and an isolated rock some 150m to the east is shown on an historic chart. Navigational instructions are to align the two St Ann's Head lighthouses and steer north by west, two thirds west, to clear the Crow Rock and the two Toe reefs.

Sources include:
Historic Admiralty Chart 2393_A6 RCAHMW digital collections sourced from the UK Hydrographic Office and first published in 1856

Maritime Officer, RCAHMW, March 2012.