The Butte de Cormeil is a strategic ridge of high ground to the north of Paris which constitutes one of the most heavily defended areas of the 'second ring' of post 1870 fortifications, hardly surprising given that the attacking Prussians mounted artillery here to bombard the capital. As well as offering distant views of Paris the hill also dominates the river Seine which curves away from its foot to the south, the market gardening area of Argenteuil and road and rail links to the north west and the channel ports. A high priority was given to completing the fort, between 1874 and 1878, which then became something of an exemplar for engineers working on other forts in the series. Its strategic significance is also shown by the extensive series of batteries and outworks which further strengthen the hill's position. Prior to these works the hill was home to three timber framed windmills. Although most of the area is heavily wooded today up until the early years of the C20 the area was kept relatively clear of trees.


The key element is obviously the Fort De Cormeil (or Cormielle) itself which has been described elsewhere notably at the French Government site 'Chemins de Memoire' and the Index de Fortification Francaise. Less well known and described are the outworks around the fort. In general terms it seems clear that these additional, largely earthwork defences, were installed to improve the defenders command of the immediate slopes of the hillside which otherwise would have remained invisible to those within the fort.

To the east of the fort  is the Batterie de Petit Montagne. this projects as a square ended salient to the south eat and is defended by a large rampart with a fire step ( see section 1) commanding the approach of the military was from the east. Central to the battery is a casemated chamber entered by a south east facing doorway flanked by two window openings, now all blocked off with concrete blockwork but originally closed by a wooden door with shutters on the windows. the dressed stone framing to these openings is identical to those used on the main fort so we may assume that it was constructed around the same time. Above the chamber are a couple of vents, one brick lined and one in concrete. the defensive ramparts curves around to the north before bending back in to parallel the military road for a short distance. A lesser rampart continues to the north protecting a shallow salient projecting to the north east. This is marked by a number of offsets and shallow traverses

The military road continues along the north east face of the fort. The lie of the land is such here that the edge of the slope is not protected by a rampart but rather oddly one has been constructed between the roadway and the ditch. This in effect creates a covered way along this side of the fort but is only present towards the northern end of the sector (see section 2).

To the north west the plateau extends some 100 metres or so from the outer edge of the fort ditch to the break in slope. This area is covered by the Battery de Belvedere to the south and further earthworks to the north. The north angle of the fort is strongly defended with a double caponier, just beyond it the military way does a dogleg bending to the south then westwards again at the point where it begins to descend the hill. This sector is covered by a curving rampart again set with several small sections of bank set at right angles to main rampart and acting as traverses (see section 3).

The Battery de Belvedere occupies a shallow promontory which projects out to the west. The defences begin just south of the cutting by which the military road descends the hill and consists of a rampart backed by a flat bottomed ditch (see section 4 ). This grows more pronounced as it curves out to the west at which point a second casemated chamber similar to the one at Batterie De Petit Montagne is built into the thickness of the bank. However this example remains open, albeit with vertical metal bars across the windows, and contains a low vaulted chamber, 12.5 m deep and 2.5 m high. The rampart and ditch continue as a well preserved earthwork (see section 5 ) as it bends back to the east and then follows the top of the slope along the eastern side of the hill. It tapers away towards the southern angle of the fort presumably as the threat from the south was thought to be less. The promontory is crossed by a number of zig-zag communication trenches surviving as shallow ditches around 2m wide and 0.5 m deep.

                                   

A curious feature of the site is tall slim hexagonal stone tower which is presumably the belvedere from which the battery takes its name. Constructed in random rubble the tower stands around 11 metres in height and has an internal diameter of 3 metres. Each angle is supported by buttresses which rise just over 3.5 metres and there is a single round headed doorway which faces west. Towards the top of the tower each face is pierced by a single square headed window. The inside bears the remains of an iron framework for a spiral stair.  Constructionally the tower is of much coarser work than the military structures described so far and it is hard to imagine military engineers building anything so obviously vulnerable to artillery attack. If the tower was built prior to the military occupation of the hill there must be some historic context for its construction which may be susceptible to further research.

Special thanks to Jean-Pierre and Christine Chalbos for their assistance with transport and translation and Verna Wass for photography Visits made June, September 2010