Richard et Cie (Richard & Co), Paris & London
According to Charles Allix (in his Carriage Clock book), Richard & Cie was founded in Paris in 1848 under a different name and added a branch in London in 1857. Then in 1867 the branch became Richard & Co. of 24 Cannon Street, London. In France, this would be Richard et Cie. Loomes says that the London business lasted until 1881. Allix also says that the inscription "R & Co" (close to your R & C) without the full trademark probably denotes a clock handled by Richard but not made by them. The Richard trademark contains an R and C with a snake's head in between, all enclosed within an oval. Thus my best GUESS is that this clock was sold sometime after 1867 by Richard as a retailer in London.