Structural Analysis of Historical Constructions - Modena, Lourenço & Roca (eds) © 2005 Taylor & Francis Group, London, ISBN 04 15363799

Study of Place Stanislas coloured pavement for its historical restoration

J.M. Mechling Université Hel1l'i Poincaré - Nancy 1, Dpt Génie Civil - IUT de Nancy-Brabois, Villers-Iés-Nancy, France

R. Elter INRAp, Ludres, Fi'ance

ABSTRACT: Listed as a World Patrimony by UNESCO, the Place Stanislas (Stanislas Square) in Nancy (France) was built in 1755. The ground ofthe Square will soon undergo a complete remodelling which aims at restoring it to its original glory. To prepare the project, a historical and geological study was carried. The research into the archives helped us to discover some unpublished documents. They present the initial state ofthe ground and appearance ofthe Square, previously unknown. They gave some valuable indications about the cobblestones (red and black limestones, layout, geometric design ... etc.) and information about the approximate cobblestone quarries. A geological study was necessary to define the nature and origin of the black cobblestones but doubt remains about the real coloured aspect of the red ones. Some chromatic analyses indicate that ali the different red rocks likely to have been used relatively close to the same ochre brown colour.

INTRODUCTlON

1.1 S/anislas Square origin

Listed as a World Patrimony by the UNESCO, Stanis­las Square was built from 1752 to 1755 by Stanislas Leszczynski, former king of Poland (1677- 1766). It is located south of the Carritire Square between the medieval town and the seventeenth century new town (Pfister 1974). The Square was named Place Royale until 1792 (French Revolution) , to become Place Stanislas in 183 I. The Square used to feature the statue of King Louis XV ofFrance, Stanislas ' step-son

but has since been replaced by a statue of the Polish King and last Duke of Lorraine.

1.2 Res/oration goal

To celebrate the 250th anniversary ofthe Square'scom­pletion, the urban council ofNancy and its agglomer­ation are undertaking a complete remodelling of lhe Square which aims at restoring the original ground and the vicinity ofthe Square. The current weight con­straints used for a public square have to be respected (pedestrian space with some occasional heavy weight

Figure I. Actual aspect ofthe Stanislas Square (photography: Town ofNancy).

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vehic\es passages for special events that demand bleachers or stands, tents, etc.). The Chief Architect at Historical Monuments is supervising the project. A study of the archives has been conducted to prepare the ground restoring project.

The aim was to discover documents about the original pavement. Search has to be conducted by a geological study to detail the different aspects and colours of the pavement mentioned in the archives.

2 NEW HlSTORlCAL DATA

Until recently, the official known documents of the Stanislas Square didn't indicate the use of colour nor geometric design ofthe pavement. In May 2003, orig­inai documents were discovered in the Public Record Office ofNancy (Archives 1755). One of these docu­ments, a quantity survey conducted by the architect to pay the pavers reveals the component and the exact geometric designs of the Square grounds at the time of its inauguration. Some contracts agreed with the pavers and the quarrymen gave information con­cerning the origin, the quality and the sizes of the cobblestones.

2. 1 Geometric design ofthe square

The pavement was essentially red in colour, underlined with black cobblestones lines. The black cobblestones were located around the base of Louis XV's statue and along the square lateral gutters. They represented the four diagonais between the corners and the central statue (Fig. 2).

2.2 Quarries location

Other documents gave a wide range of information about the work order from the quarry to the grounds. The stones were ali extracted from less than ten kilo­metres from the Square. They carne from different local towns, Art-sur-Meurthe for the black cobble­stones, Dommartemont, Malzéville, Pixérécourt and Vandoeuvre for the red ones. Today, these sites are too vast and contain different rocks than the past black and red cobblestones. Special geological investigations will be necessary (refer to below).

2.3 Cobblestones and characteristics ofthe builder s yard

The cobblestones were sized on the quarrying place. As shown in an agreement between the architect and the local paver Jean Maizieres on July 15th 1754 and as found in the archives, the work had to be very precise. Indeed, the layout of the pavement pre­scribed a selection of cobblestones in the quarries;

Figure 2. A view of the Stanislas Square sourced from lhe painting ofPange. (Photography: Town ofNancy).

sizes had to be of approximately 0.25 to 0.29 m in length, 0.20 to 0.26 m in width and 0.26 to 0.29 m in high. They couldn't be sensitive to frost. Another doc­ument specifies the use ofa good quality rock without imperfections particularly the c\ay beddings.

The cobblestones were carried to the bui lder's yard by the pavers (Archives 1755). Thereafter, the cob­blestones were placed on a sand or gravei levei with a disposition that allowed for crossed joints. The pavement was then covered with sand.

2.4 Remarks abotll this new documentation

Surprisingly, the documents found in the archives gave new information about the two colours of the pave­ment and their geometric designs totally ignored by the official iconography.

Only one painting, which can be seen in the castle of Pange (sixteen kilometres to the north of Nancy), shows how the cobblestones were installed (Fig. 2) . Red and black cobblestones are visible as the black diagonais that leading to the corners to the statue of Louis XV This pavement was preserved as far as the French Revolution. A new quantity survey from May 30th 1789 indicated that refection works were neces­sary (Archives 1789). They were eventually stopped by the Revolution. The monarchy marks as the statue dis­appeared in 1792. The first geometric pavement design to highlight the statue were changed and disappeared from the collective memory ofthe inhabitants.

3 FIRST GEOLOGICAL ARGUMENTATION

3.1 Nancy geological context

From a geological point of view, Nancy is located on the eastern fringe of the sedimentary basin of Paris. The town and its vicinity grow in a c\ayey dip, sur­mounted by a calcareous table-Iand and its residual hill, respectively to the west and north-east. A river lhe Meurthe runs inside the dip not far from Nancy's city centre. Local stratigraphy (dated from the Juras­sic period) also shows two blocks. At the bottom the first layer (geological stages Hettangian-Sinemurian, Pliensbaschian, Toarcian) mainly contains c\ays with a few limestones and sandstones on 250 to 270 metres

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high. The second layer (geological stages Aalenian and Bajocian) is a continuai succession of severa I limestones lithofacies on 120 metres deep. The rocks susceptible to have been used for the pavement have to be found in some geological strong sedimentary beds in exclusion oftoo many clayey materiais. These rocks must correspond to the initial colours criteria. Histori­cal archives could help us to determine more precisely locations of ancient quarries.

3.2 Colours present in locallithostratigraphy

In this lithostratigraphy, we can effectively find again the different colours described in the historical writ­ten documents. The oldest sedimentary beds from Hettangian-Sinemurian, Pliensbashian and Toarcian contain dark lithofacies of grey, blue-ish and black colours. With the exception of a particular limestone bank of a I or 2 metres thick, named Calcaires ocreux; initially black, it can progressively takes a rusty colour with the weather alteration.

Just above, Aalenian geological stage coincides with the regional iron ore well known as Minette Lorraine and extracted during the nineteenth and the first part ofthe twentieth centuries. Its petrographical aspects and colours do vary. In this geological sedi­mentary beel, shades encountered are caused by iron oxides variation and concentration. They can be grey, green, reei, brown, with many sort of rust or orange shades (Bubenicek 1961).

Above, lower Bajocian allows calcareous rocks still containing a few iron oxides. The shades are there­fore systematically ochre brown, rust or even red with a more or less grey colour adjunction. Local encrinitic limestone, Calca ires à entroques, is occa­sionally named red rock, Roche rouge, by quarrymen and geologists.

At the top of the local stratigraphic series, colours from the middle Bajocian are very different from the previous rocks. Shades are typically white-ish like the white oolite sedimentary beel, Oolilhe blanche, or grey­ish like coral limestone, Calcaires à polypiers. These different specific colours are easily recognizable in the road slopes that climb the table-Iand over Nancy.

3.3 Preliminary results

The local towns of Malzéville, Pixérécourl and Van­doeuvre match the Aalenian and Bajocian geolog­ical stages, whereas Art-sur-Meurthe relates to the Hettangian-Sinemurian.

The comparison of these quarries coming from the different towns above named and as mentioned in the archives, with the first geological argumentation and the colour oftheir extracted rocks is consistent (Tab. I) and allow us to make initial conclusions. Hettangian­Sinemurian limestones have been extracted for the

Table I. Links between the Archives localities and the geological stages.

Stages

Mid. Bajocian Low. Bajocian

Aalenian

Toarcian Pliensbaschian

Hettangian -Sinemurian

Petrography

Limestone Limestone

Limestone

Marle MarJe/ Sandstones MarJous-

caJcareous

Colours

White, grey Ochre brown Grey Red, orange Brown Green, grey

Dark grey Black BJue-ish

Local towns

Malzéville Pixérécourt Vandoeuvre

ArtIMeurthe

black cobblestones whereas Aalenian andlor lower Bajocian limestones have furnished red materiais.

We have to complete these previous indications with some field observations to confirm the real aspects of the two sorts of cobblestones.

4 PETROGRAPHICAL ASPECTS OF THE COBBLESTONES

4.1 Black cobblestones

The case of the black cobblestones is simple beca use sedimentary bed Calca ires à Gryphées is the only one allowing black or dark grey limestone in the local statigraphy. Furthermore, they could be no doubt about the black cobblestones origin as its presents in Art-sur-Meurthe, was mentioned in the archives.

Today, there isn 't any quarry visible in this local area but archives also mentioned a special tenancy rental contract for the purpose of extracting those stones. The original cobblestones sources was about 30 cm cubic and covered approximately 7.5% of the Square (about 850 m2 compared to 11300 m2) representing a total volume of 240 m3 . A very small production of quarry was necessary for as the stripping and the waste rocks. At the end of the lease and the extraction being finisheel, farm cultivation replaced the quarry act ivity. Fifteen kilometres to the west, an important quarry is currently in use in this sedimentary bed by a cement company.

This Calca ires à Gryphées is an alternance of cal­careous and marly banks of 10 cm to 60 cm high. Fossils (ammonites, ancient bivalvia like Gryphea arcuata) can be very abundant in particular places and the limestone characteristic aspect is generally con­stant. The stone texture sub-lithographic is very thin (Fig. 3) and therefore cobblestones are not very dif­ficult to size. On the other hanel, these limestones are generally a little clayey (about 5%) and also present some low resistances to the freeze and thaw action.

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Figure 3. Aspect of the black limestone Ca/caires à Gryphées, note the very thin texture (width of lhe fie ld of view: 14cm).

4.2 Red cobblestones

Find the original colour ofthe red cobblestones is more complex than fo r the black stones for two main reasons. At first, a red-ish colour could correspond to three geological calcareous sedimentary beds of geologi­cal stages Aalenian and lower Bajocian. Secondly the archives from the local towns previously mentioned report these three different red rocks sedimentary bed for systematic extraction. For each one, Minette Lor­raine, Calca ires sableux and Calca ires à entroques we have to consider, petrography and colours ofthe lime­stones, aptitude for stone cutting and performances, and the eventual presence of historical quarries.

Minette lorraine (Aalenian): In Nancy area, this formation is the only one that can have some really pronounced red colours among others like those previously named in Section 3.2. It's a set of carbonaceous (oolites, ossicles) or siliceous (quartz) detrital deposit, from 10m thick. There is a high concentration offerruginous minerais such as iron sul­phurs (pyrite ... ) and iron oxides (limonite . .. ). The rock cementation is made with carbonates (calcite . . . ) and ferruginous compounds.

Around Nancy, this sedimentary bed has been inten­sively and industrially used in underground mines and presents a characteristic microfacies of ferruginous oolitic limestone (Fig. 4). However these rocks are generally toa clayey and have insufficient mechanical properties to cut cobblestones. Only a few blocks have been used in a wall of a mediaeval castle established at 40 km south of Nancy in the village of Vaudémont however nobody is aware of any quarry used for blocks extraction.

Calcaire sableux (lower Bajocian): This geologicallevel is defined by a th in ochre brown limestone layer that contains a variable quantity of

Figure 4. Microscopic view of the ferruginous ooliles in Minefte Lorraine (magnification: x 25).

Figure 5. Homogeneous aspect of the Ca/caires sab/eux (width ofthe field ofview: IOcm).

quartz grains (between 5 and 40%) and clayey min­erais. Observed through a microscope, most of the others elements are bioclastic materiais as fragments of echinoderme, serpula and small bivalvia wich are coloured in ochre brown. Their good wide spread among the rock combined to the iron oxides present in the carbonaceous cement, give a stable colour and aspect to the rock (Fig. 5).

In a lot of reefs, clays and quartz induce the for­mation of thin lamina (I to 2 mrn high), responsible of an important rock breakdown (Castaing 1972). In these conditions, a production of cobblestones is not easy and requires the selection of the most favourable banks of stone.

An ancient quarry is known in the local area of Vandoeuvre and is now used for modem urbanization.

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Figure 6. Heterogeneous aspeet of the Ca/eaires à entroques. Note the differenee between the bottom part ofthe sample (grey limestone with many small blank ossieles) and the large red spot above (width ofthe field ofview: 15 em).

Figure 7. Relatively homogeneous appearanee of the Ca/eaires à entroques presenting a thin spotty aspeet (width ofthe field ofview: IOem).

It may be possible that other ones existed and progres­sively disappeared for the same reason. We don't find any indication concerning their eventual location and period of activity.

Calca ires à entroques (lower Bajocian): This sedimentary bed named, Calca ires à entroques, is irnrnediately placed above the previous (Calcaires sab/eux) . There is no real evident limit between those two calcareous layers and their aspects can sometimes be similar. Nevertheless, the frequently encountered rock is a massive encrinite as a result of an accumula­tion between marine animal fragments (ossicles) and cemented by calcium carbonates (calcite).

In the past, two ancient important quarries existed in this geological formation and are now localities, Vandoeuvre, and Dommartemont. The first one is located on a cadastral survey from 1805 (50 years after the ground edification) while the second was in use during the 14th century for the construction of a gate on the Meurthe. Our field observations especially

close to those two quarries have shown that encrinite usually have two coloured different aspects. The more cornrnon is a grey facies with red orange milimetrik or a couple of centimetres large spots (Fig. 6) caused by a high enrichment of iron oxides (limonite . . . ). But this limestone can regularly be more homogeneous with a very thin orange spotty aspect (Fig. 7). In this particu­lar case, iron oxides are well scattered in carbonaceous cement and porosity from small size.

The sedimentary bed gives acceptably good mech­anical properties but is not really suitable for a cutting. Actually many quarries uses this rock for crushed gran­ulates generally used as seating ofroads. From a nor­mative aspect, impact strength (Los Angeles test, NF P 18-573) or attrition strength (Micro Deval test, NF P 18-572) present some moderate results (LA = 30 and MDE = 40) (Zennir, 1996). However those mechani­cal properties are better than those of the two previous formations (Minette Lorraine and Ca/caires sableux) that are never used in the actual public works.

4.3 What does the red rock rea//y look like?

It 's very difficult indeed impossible to give the real aspect ofthe red rocks as simply named in the archives. In some cases, it can correspond to an unvarying rock aspect with a more or less pronounced ochre brown colour (Calcaires sableux and Calca ires à entroques in several banks). In some other cases, it corresponds to a spotty rock resulting from the combination of a grey­ish colour with red orange to rusty spots (Ca/caires à entroques) .

This first aspect is the same than the one represented on the painting kept in the castle of Pange (Sec­tion 2.4). Meanwhile, many ancient quarries would principally furnish the second aspect. The uncertainty persists.

In our historical remodelling, we can only define the prevailing colour ofthe different rocks and three cor­responding facieses. During the initial ground edifica­tion, many quarries were used and most cobblestones had probably not the same aspect. We can estimate the total red cobblestones volume about 3200 cubic meters (92.5% from 11300 m2

, 30 cm thickness). This volume is toa high for a constant production in those geological beds.

The lower Bajocian doesn't allow any good rock for quality building stones. As we can see in the next section, the mechanical properties ofthose limestones are not sufficient for actual technical applications.

5 SUBSTITUTION MATERIALS FOR THE RESTORATION

The use ofthe original black and red limestones raises a lot of issues for the remodelling of the Stanislas Square. We shall remember that the cobblestones were

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carefully chosen before their use and despite those pre­cautions, the original pavement was rapidly damaged (see Section 2.4).

In first instance difficulties appear into making the different cobblestones. It would be very difficult to dress cobblestones in the ochre brown limestone from the lower Bajocian, at reasonable cost. Furthermore, the existing quarries open in those limestones pro­duce crushed granulates and consequently use a very different quarrying technique that the one used for the cutting stones. Furthermore, greater difficulties stand with regards to the durability of the cobble­stones in relation to lhe weather or occasionally heavy weight vehicles circulation (special events, march past). Most ofthose limestones are easily cracked by lhe frost and show bad impact and attrition strength, except the encrinitic limestone, Calca ires à entroques, for acceptable characteristics. These limestones full of iron oxides would tend to change and generally become red with high temperature. At times, politi­cal demonstrations takes place on the Stanislas square and it is necessary to anti cipa te, an eventual fire started by the demonstrators and its consequences on the ground.

For those above reasons, the local authorities and the Chief Architect aI Historical Monuments decide to choose stronger materiais such as better quality lime­stones or siliceous rocks. These substitution materiais will have to be in conformity with the norms and will have to match to the colour of the original pavement. The previous descriplions gave any qualitative colours descriptions that greatly depend on personal percep­tion. To avoid this mistake, we carried some specific analyses: colour of representative samples had been measured with an accurate chromatic study.

6 COLORlMETRlC ANALYSES

6.1 Methodology

The colorimetric analyses were carried with two types of three dimensional colour spaces, Lab and LCh, defined by the CIE, International Commission on Il/umination (CIE 1986).

CIE Lab system is the most commonly used colour space and is based on human perception of colou r; the three colour receptors being reei, green and blue in the eye. This result in three sets of signals are sent to the brain: light or dark, red or green, and yellow or blue. They are opposite meaning one receives a red signal or a green one but not both. This opponent type colour space is derived mathematically from the CIE values.

CIE LCh system is similar lo the CIE Lab colour space, except that it describes the location of a colour in space by using polar coordinates, rather than rect­angular coordinates.

L is a measure of lightness of an object, and ranges from O (black) to 100 (white). It indicates the reflecting properties of an object and also reveals its more or less dark surface.

a is a measure of redness (positive a) or greenness (negative a).

bis a measure of yellowness (positive b) or blueness (nega tive b).

C is a measure of chroma (saturation), and repre­sents the distance from the neutral axis.

h is a measure ofhue and is represented as an angle ranging from 0° to 3600

• Angles that range from 00

to 90° are reds, oranges and yellows. 900 to 180° are yellows, yellow-greens and greens. 1800 to 2700 are greens, cyans (blue-greens) and blues. From 270° to 3600 are blues, purples, magentas, and return again to reds.

6.2 The samples and results choice

Eight representative samples (noted A to B) were chosen in the different geological sedimentary beds having supplied the cobblestones. Most ofthose sam­pies carne from the reddish rocks (Aalenian and lower Bajocian) with reference to the problem ofthe red cob­blestones. The black limestone has already the same aspect (colour and structure), so only one measure was necessary.

For each sample, a polished plane surface was made and several tests were carried on it. The above Tables 2a, b contains the obtained values.

6.3 Reading

At first, it is not surprising (but normal) to see a sig­nificant difference between the results of the black limestone (sample H) and those ofthe red ones. Param­eters a, b, C and h respective values are -0.29, 0.45 , 0.53 and 123.30, to 8.19,17.90,19.73 and65.54forthe average values ofthe red rocks. On the other hanel, it 's difficult to clearly characterize the differences between the red rock sample values.

That is why we express I1Eab , the difference or the distance between two colours, in the CIE Lab system, with the above equation 1:

(I)

where I1Eab is the colours difference; I1L the differ­ence between the L values ofthe two different colours; idem for l1a and I1b, with a and b values.

From O to 1, the colours difference is tiny. If this value is above 3, the visual difference is not very flaggering. Beyonel, the difference becomes more and more visible.

Ali the values between each pair of samples have been calculated and figured in the next table (Tab. 3).

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Table 2a. Lab, Colorimetric results.

Colorimetric analyses

Sedimentary beds Samples L a b

Calca ires à entroques A 52.43 7.49 17.69 B 56.92 6.60 16.99 C 51.53 6.22 14.52

Calcaire sableux D 52.62 6.90 16.91 E 53.59 8.52 20.28

Minette F 45.72 10.04 21.85 G 42.67 11.58 17.06

Calca ires à G/yphées H 41.31 - 0.29 0.45

Table 2b. LCh , Colorimetric results.

Colorimetric analyses

Sedimentary beds Samples L C h

Ca/atires à en/roques A 52.43 19.21 67.06 B 56.92 18.22 68.76 C 51.53 15.79 66.82

Calca ire sab/ellx D 52.62 18.26 67.81 E 53 .59 21.99 67.21

Minelle F 45.72 24.05 65.32 G 42.67 20.61 55.83

Calca ires à Gryphées H 41.31 0.53 123.3

Table 3. Colour di fferences !'J.Eab between the different samples of red rock.

A B C D E F G

A O 4.63 3.63 1.00 3.02 8.30 10.60 B O 5.94 4.30 5.05 12.70 15.09 C O 2.71 6.54 10.10 10.66 D O 3.86 9.04 10.99 E O 8.16 11.78 F O 5.88 G O

At first, we can comment the results obtained between the samples taken in the same sedimentary bed. For the Ca/caires à enfroques (three samples), the values vary between 3.53 and 5.94. In the formations Ca/caires sab/eux and Minette Lorraine (two sam­plings, each) the respective colour difference values are 3.86 and 5.88. The differences 6.Eab are superior to 3 and some colour variations appear as it was described in the petrography (see Section 4.2). The smallest value, 3.86, corresponds to the Ca/caires sab/eux, the most homogeneous sedimentary bed.

Regarding the values of the black limestones, Ca/caires à g/yphées, it is possible to take those results

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Table 4. Average values for the two cobblestones colours.

Average colorimetric values

Colour L a

Red limestone* 53.42 7.15 Black limestone 41.31 -0.29

b

17.28 0.45

C

18.69 0.53

h

67.53 123.30

* limited lO lhe Calca ires sableux and Ca/caires à en/roqlles sedimentary beds.

as a reference. Indeed we regard (see Section 4.1) this geological leveI as a homogeneous one.

Now we can compare the different colours differ­ences 6.Eab average values calculated between each formation. For the two sedimentary beds Ca/caires à entroques and Ca/caires sab/eux, the average differ­ence is only 3.77. This value is approximately on the same scale of size that the ones previously obtained between the samples of an individual formation. We can then rely on the colours difference in and between those two sedimentary beds as equivalent. It is not the case with the Minette Lorraine, where the typical colours differences 6.Eab vary between 8 and 15.

Summarize those colour analyses, we can note that the two sedimentary beds named Ca/caires à entro­ques and Ca/caires sab/eux are relatively similar. Their average parameters (Tab. 4) could be used as a colori­metric reference for the choice of alternative materiaIs similar to the original colours of the Stanislas Square pavement. This colour represent a good arrangement as it takes in account most ofthe lithofacies that could be initially used on the eighteenth century. Whatever taken decision as whether to use a regular or a spotty ground aspect, the general new aspect will be relatively close to the historical colour.

7 CONCLUSION

Upon their accuracy the newly discovered archives completed with some geological investigations allow a real knowledge enrichment for the project and constitution specifications.

This study allows to find the historical red and black colours, the geometric design ofthe pavement as well as information about the growth and cobblestones hewing or installation. The original black limestones used for cobblestones are precisely defined while a small doubt remains between two adjacent sedimen­tary beds for the red cobblestones. The red colour that is in fact an ochre brown tone, could be from a homogeneous aspect or a fine spotty one. However, a careful observation of the colours linked with an accurate chromatic study (CIE Lab and LCh methods, reflexion spectrometry) indicate that ali the different reddish rocks likely to have been used are relatively close in term of colour.

This research also gives a clear indication of the poor mechanical properties of the initial materiais. Consequently, the shortly true historical restoration will have to use stones of greater quality that allow the elaboration of a pavement globally similar to the original one.

The conclusion of this study is useful and can be used as a basis for a new substitution materiais choice.

REFERENCES

Archives 1755. Série CC 630- 691. Public Record Office ofNancy.

Archives 1789. Série AA nO 15. Public Record Office ofNancy.

Bubenicek L. 1961. Recherches sur la constitution et la repartition du minerai de fer dans I' Aalénien de Lorraine. Annales de ,'ENSG et du CRPG tome 8: pp 5-204.

eastaing J. 1972. Contribution à l'étude sédiment%gique du Bajocien de la région de Nancy. Ph-D Université Henri Poincaré, Nancy I .

eIE 1986. C%rimetry, Technical report /5.2. Vienna: Bureau central de la elE.

Pfister C. 1974. Histoire de Nancy. Paris: Berger-Levrault Ed. Zennir A. 1995. Bétons ca/caires en Lorraine - Utilisation

des granulats du Bajocien de Viterne pour la formula ­tion de bétons courants. Ph-D Université Henri Poincaré, Nancy I .

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