Above: "The Roman Tower at Caerleon, Monmouthshire" published 15th August 1783 by S Hooper. From The Antiquities of England and Wales by Grose.

The text accompanying the print stated:

"THE building whose ruins are here delineated stands at Caerleon in Monmouthshire, near the bridge laid over the river Usk; it is generally supposed of Roman construction, there having been a Roman station at this place, and the remains of an Amphitheatre; Baths, and other Roman works, being still discoverable, about and within the enceinte of its walls, which are said to have been near three miles in compass.
It seems difficult to assign the use for which this tower could have been built, its size for which the figures may serve as a scale, shew it could scarcely have been intended for defence, as from its smallness it could contain but very few men; perhaps it might be intended for a stair-case, or as the towers in Burgh caftle near Yarmouth, the Gariononum of the Romans, for a buttress to prop and strengthen the adjacent wall.

This view was drawn anno 1778"

Coxe (1801, An Historical Tour In Monmouthshire) referred to the above illustration and described its location as being "Close to the southern extremity of the bridge, in the district sometimes called the village of Caerleon". But was he confusing this tower with another? It is difficult to tell from the illustration, but the original text does not mention the tower being on the Southern side of the river. (See the sketch by Samuel Loxton of the tower on the Ultra Pontem side of the river.)

Below we can see a reworking of the print. It appeared in The History And Legends Of Old Castles And Abbeys, part 13, published May 1875 by John Dicks, 313 Strand, London. As well as a cobbled together history of Caerleon this also included the legend of The Last of the Caerleons which you can read by following this link.