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