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Canadian Historic Sites: Occasional Papers in Archaeology and History No. 2

A "Rescue Excavation" at the Princess Half-bastion, Fortress of Louisbourg

by Bruce W. Fry

The settlement of Louisbourg was started by the French in 1713 on Cape Breton Island, Nova Scotia. In 1745, the French surrendered to a combined force of New Englanders assisted by the British, although the fortress was later returned to the French in 1749. The British once again successfully besieged the fortress in 1758 and, fearful that it would be restored to the French, systematically demolished its fortifications in 1760.

Edward McM. Larrabee (1970) described the archaeological research at the Fortress of Louisbourg which took place from 1961 to 1965. During that time, attention was concentrated on the King's Bastion, although there were several minor excavations in other locations of the fortress. One of these briefly mentioned by Larrabee is that of the author's salvage work on the Princess Half-bastion in 1964. This paper describes that excavation and its results.

The Princess Half-bastion is located on the south shore of the rocky promontory occupied by the ruined fortress, and is at the end of the fortified front of bastions which defended the French town against attack from the country (Fig. 1). Remote from the King's Bastion complex and the main area of the town, the Princess Half-bastion has, to date, received little attention under the current restoration programme, although documentation has been recently studied. In spite of the concentrated effort on the Citadel, however, it was felt worthwhile to devote some time to a small-scale rescue operation at the Princess Half-bastion when certain features were exposed by severe storms and high tides.

1 Fortress of Louisbourg — map showing location of defensive works. (click on image for a PDF version)

The bastion was constructed so that its flanked angle, the right face and right flank confronted the country in a conventional manner, but its left face was parallel to the shore. The eroded appearance of these seaward-facing ramparts, together with an appreciation of the British demolition in 1760 in this area (Fig. 2) gave little hope that anything of significance had survived. But in November, 1963, storms and high seas exposed some 30 dressed sandstones ("cut stones") on the beach. Because of the cut-stone study then in progress for the Citadel (the stones provided architectural information of prime importance to the restoration), the significance of the stones found on the beach was readily appreciated, and they were duly recorded, catalogued and removed to safe storage.

2 Copy of the British engineers' demolition plan, 1760.

The following spring, further erosion along the seaward defences exposed a section of rubble masonry escarp, still surviving intact. There was, moreover, an indication that a cut-stone feature was also surviving intact, incorporated in the escarp (Fig. 3). Thus the opportunity was taken to examine a well-preserved section of the defences, albeit a small one, before further erosion and collapse could occur.

3 The small-arms loop as first discovered.

The archaeological investigation was limited to a trench across the escarp to expose the feature completely, to determine its relationship to the defences and to remove it before it was damaged further. No historical information was available at the time.

As originally exposed, the cut-stone feature appeared to be a musket slit (Fig. 3); when fully uncovered, it proved to be an unusual example of such a defensive work. The stones had been cut to form a conventional musket slit, but at the bottom the slit opened out into a circular aperture (Figs. 4 and 5). The feature, best referred to perhaps as a loop-hole for small arms, comprised 18 pieces of dressed sandstone, all hand-cut to a neat finish, but not so precise as to form a perfect circle at the round aperture, nor to be completely symmetrical. The exterior face of the stones was cut to a batter of 1 in 12 (corresponding presumably to the batter of the seaward escarp). Apart from the batter and the exterior face finish (rough pointed), the loop-hole was identical when viewed from front or rear: slit and aperture flared equally in both directions from a constricted centre. At its narrowest, the slit was 4 in. wide, and the circular aperture 9.5 in. in diameter. The slit flared out to a width of 10 in. and the aperture below to a diameter of 21 in. The entire unit was 5 ft. high.

4 The loop-hole fully exposed.

5 Isometric drawing showing the construction of the loop-hole.

Because this section of the defences commanded rocky shallows, there was little need to guard against large enemy vessels sailing within range, but rocky bluffs immediately to the south of the Princess Half-bastion created a large blind spot which would enable small boats to land without being exposed to fire. Lest a force attempt an overland advance from this protected beach, the landward defences were strengthened with a ravelin in the ditch. The seaward defences were presumably designed, therefore, to counter any movement along the shallows, either by small boats or by wading troops.

The narrow slit of the loop-hole was obviously designed for a musket, but the use for which the circular aperture was intended is conjectural. Possibly a musketeer, by kneeling, could command a larger field of fire. More effective from a tactical point of view, however, would have been the use of a small (four to six pounder) field gun loaded with shrapnel to sweep the shallows.

Excavation showed that access to the loop-hole was by means of a gallery running along the flank (Fig. 6). This had been formed by constructing a rubble masonry wall parallel to the escarp and spanning the gap with a rubble masonry vault lined with brick. Earth was tamped down on top of the roof of the gallery to complete the rampart fill. A plank floor was laid on natural clay along the length of the gallery. The width of the gallery at floor level measured 9 ft., but distortion of the masonry due to a demolition charge which had been exploded nearby affected the accuracy of measurements within the gallery, it was difficult, also, to determine the height of the gallery. The spring of the vault was 5 ft. 9 in. above the floor: the curvature appeared to be considerably flatter than that of a barrel vault; and a height of about 8 ft. above the floor would therefore seem to be reasonable.

6 Section through the seaward defences of the Princess Half-bastion. (click on image for a PDF version)

The length of the gallery was not determined during the course of this excavation, but there were clear indications that several loop-holes had existed in it. Distribution of cut-stones along the beach, together with visible remains of brick relieving arches similar to that above the cut-stone lintel of the intact loop-hole, suggested that a minimum of three more loop-holes, spaced at approximately ten-foot intervals, had existed formerly.

Excavation also provided evidence of modifications to the gallery. The loop-hole itself had been thoroughly plugged with rubble and lime mortar (Fig. 4). Moreover, an additional wall had been constructed against the interior of the escarp (Fig. 6), thus effectively blocking any access to the loop-hole from the inside. There was every indication that this wall continued the length of the gallery, blocking the other loop-holes as well. On the exterior, layers 13 and 14, as shown in Figure 6, overlay the footing of the escarp, and may reasonably be assumed to be construction debris deposited at the time the gallery was modified.

From both of these layers came sherds of pottery and glass. The pottery sherds proved to belong to one vessel—a bowl of Staffordshire ware with a base diameter of 4.5 in., of a style that was common throughout the first half of the 18th century. Not enough glass was present for positive identification, although it appears to have belonged to a British vessel common around 1750.

7 Reconstruction of Staffordshire pot.

The British, who occupied Louisbourg from 1745-49 following the first siege, may have been responsible for modifications to the gallery. If this were the case, it would explain the presence of British artifacts in the layers associated with repair work, although excavation revealed no clue as to why the occupying forces would take an interest in this part of the defences.

Some time after the excavation, historical evidence was found which corroborated the archaeological conclusions and explained the reasons for the blocking: the British, finding that these coastal defences were of little importance, sealed up the loop-holes and converted the gallery into a powder magazine. The French, on their return to Louisbourg, clearly did not think it worthwhile to reverse the decision to close the gallery.

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