Rare English silver and tortoiseshell verge watch Circa 1750

Silver and tortoiseshell watch in pair cases
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A pair cased pocket watch with extremely rare movement made by James Rousseau in London, England, circa 1750. Both later cases of this watch were especially made for the movement. The white enamel dial has Roman hours, an outer minute track, outermost Arabic five minute numerals and fine steel poker & beetle hands. The numbered movement has silver decorations, is set with stones, and the cock and pillars are probably all set with tourmalines.
The movement is signed.
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Diameter: 50 mm
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Weight: 97 g
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Signed: Ja. Rousseau London
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No comparable verge movement from this period with such decoration is known. This may be a unique piece. Unfortunately, the original, presumably precious case has been replaced.
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Rousseau
James Rousseau was a watchmaker, active in London during the mid 18^th century and well known for his connection to a prestigious Swiss horological dynasty. He often signed his timepieces with “Jas Rousseau”.