E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A quack; so called from one Rock, who was the Holloway of Queen Annes reign.
Oh, when his nerves had once received a shock,
Sir Isaac Newton might have gone to Rock.
The Ladies Rock. A crag in Scotland under the castle rock of Stirling, where ladies used to witness tournaments.
In the castle hill is a hollow called The Valley about a square acre in extent, used for justings and tournaments. On the south side of the valley is a small rocky pyramidical mount, called The Ladies Hill or Rock, where the ladies sat to witness the spectacle.Nimme: History of Stirlingshire, p. 282.
People of the Rock. The inhabitants of Hejaz or Arabia Petræa.
Captain Rock. A fictitious name assumed by the leader of the Irish insurgents in 1822.