Each card measures about 5.75 x 9 cm., engraved image on the recto with 'Rock & Co., London' in the image, on 19 cards, two cards have J. S & Co., London, below the image. Verso blank. Many of the 21 cards have a printed series number, the highest being 101, the other number no higher than 48. Three cards have no number. The cards by J.S have the numbers 4 and 5, so they may have been part of a smaller series. 'J. S.' are the initials of J. Simmons.
Among the group four cards have a hand-stamped retailer's name on the verso, 'W. Weddell 48, South Bridge Edinburgh'. The Scottish Book Trade Index records Weddell working out of 48 South Bridge between 1850-70.