I have taken the liberty of transmitting to your Lordship the accompanying Communication. It is an Extract from a Letter sent to me by my brother, who has been on a tour in France, and the account he gives of the astonishing monument at Carnac I have presumed may be interesting, the more especially as I believe there exists no accurate description of this wonderful structure. In the recent work of Mr. Higgins on “the Celtic Druids,” we have only M. Cambry's account of it, with copies of his illustrative plates, and these are shown by the present relation to contain several errors and exaggerations.