The nested double squares are very characteristic of small Gallo-Roman temples. Estrées-sur-Noye (Somme).
Small rural Gallo-Roman temples have been familiar sites in England, Normandy, Burgundy, and pretty much everywhere in Gaul, yet this type of structure was unknown in the Somme before aerial prospecting. Using this technique, some forty sites have been found, as well about about twenty in the Oise, Aisne, and Pas-de-Calais departments. White stone foundations in the middle of large silted plains are visible in wintertime, even from far off! They take the form of two squares, one set inside the other. The central square is the base of the cella, i.e. the temple itself, in which the venerated god would be placed. Caesar tells us that "the Gauls honor their gods by turning around them." This explains the presence of a adjacent gallery where worshipers could walk. The outside white square, easily seen in photographs, corresponds to the foundation of this gallery.
The dimensions of these temples are generally consistent. The overall width is between fourteen and eighteen meters on a side. Sometimes, temples are not completely square (18 X 14.4 meters at Rumaisnil in the Somme). Judging from aerial photographs, the walls that supported the cella and those that supported the gallery had about the same thickness. Nonetheless, in several cases the exterior foundations are less imposing if, as is generally acknowledged, these fana consisted of a central tower to which was added a simple exterior arcade protected by a sloping roof (Estrées-sur-Noye, Hornoy, etc.). Simply examining the photographs does not allow us to state whether the central portion was paved or lined with stones, except at Proyart (Somme). In several cases, one can make out a flight of steps, such as at Guillancourt and Barleux. When the entrance is visible, it faces the direction of the rising sun, with the sole exception of Cantaing (Nord).
The foundations of the small square temple (fanum) appear in white. Green areas indicate enclosures, pits, and postholes. Cocquerel (Somme).
Foundation lines of a temple and its adjacent buildings à Proyart (Somme).