Source: Abraham Bogaert, C. Julius Cesars Aantekeningen Der Gallische (Caesar’s Commentaries On The Gallic Wars), published in 1709
This is an example of a wire watermark. It depicts a shield partitioned 'per pale' with three "X"s in the center partition. On either side of the shield are lions as supporters. The top portion of the image is cutoff, making it impossible to determine if a crown surmounts the shield.
Additional Book Information
C, Julius Cesars Aantekeningen Der Gallische, Burgerlyke, Alexandrynsche, Africaansche, En Hispanische Oorlogen. Abraham Bogaert. Met kopere plaaten verciert. (Published at) Te Amsterdam: By Nicolaas ten Hoorn, Boekverkoper. 1709