The distinctive features are:
But this is usually the form of all the Gallic walls. Straight beams, connected lengthwise and two feet distant from each other at equal intervals, are placed together on the ground; these are morticed on the inside, and covered with plenty of earth. But the intervals which we have mentioned, are closed up in front by large stones. These being thus laid and cemented together, another row is added above, in such a manner, that the same interval may be observed, and that the beams may not touch one another, but equal spaces intervening, each row of beams is kept firmly in its place by a row of stones. In this manner the whole wall is consolidated, until the regular height of the wall be completed.
... it possesses great advantages as regards utility and the defence of cities; for the stone protects it from fire, and the wood from the battering ram, since it [the wood] being morticed in the inside with rows of beams, generally forty feet each in length, can neither be broken through nor torn asunder.
About 30 structures of this type have been excavated, mainly in Gaul, but extending to the upper reaches of the Rhine and Danube. The example at the sea promontory fort of Le Camp d'Artus, at Huelgoat, was excavated and reported by Sir Mortimer Wheeler.
The murus Gallicus contrasts with other construction styles:
At Manching an earlier murus gallicus wall was rebuilt in the pfostenschlitzmauer style.
The definitive modern reference on hillfort construction, with extensive descriptions, comparative analysis, photographs of modern reconstructions, and even results of experiments burning reconstructed walls.