OR/13/015 Appendix 1 - Field descriptions of Falkirk building stones

Gillespie, M R, Everett, P A, Albornoz-Parra, L J, and Tracey, E A. 2013. A survey of building stone and roofing slate in Falkirk town centre. Nottingham, UK, British geological Survey. (OR/13/015).

This appendix contains a summary description and associated photographs for each of the twenty building stones recorded in the Falkirk THI area (see section 3). A near-focus photograph (at the scale of a masonry block) is provided with the description for each stone, to illustrate its typical colour and character. For sandstones and limestone, a photograph of the reference building on which the description was based is also provided. For modern buff sandstones, which are commonly present as indents and additions to original masonry, the photograph of the reference building is centred on the indented blocks or additions.

Stone code:	SB1
Stone name:	Buff sandstone 1
Reference building:	1 Glebe Street/16-18 Newmarket Street PRIMARY_KE 963254
Colour of exposed surfaces:	various shades of buff
Grain-size:	medium-sand-grade to coarse-sand-grade; granule-grade locally Primary sedimentary structure: blocks are commonly bedded; parallel bedding, cross-bedding, parallel lamination, laminated foresets and rare wispy lamination are all developed locally; buildings usually contain some uniform blocks, and in some buildings most blocks are uniform
Distinctive features:	rare flakes of carbonaceous matter; gritty locally
Composition:	impure

Stone code:	SB2
Reference building:	Vicar Chambers, 27-35 Vicar Street PRIMARY_KE 963213 & 963214
Colour of exposed surfaces:	buff, with an orangeish to pinkish tinge locally
Grain-size:	fine-sand-grade to medium-sand-grade
Primary sedimentary structure:	most blocks are uniform; rare cross bedding; convoluted structure visible on surfaces of soiled/weathered blocks
Distinctive features:	none, but this stone is rarely visible at ground level
Composition:	impure
Comments:	some blocks are gritty

Stone code:	SB3
Stone name:	Buff sandstone 3
Reference building:	1 Princes Street PRIMARY_KE 963222
Colour of exposed surfaces:	light buff to very light buff (almost white)
Grain-size:	fine-sand-grade to medium-sand-grade
Primary sedimentary structure:	uniform
Distinctive features:	scattered flakes of carbonaceous matter; faint Liesegang bands; scattered brown mud flakes locally
Composition:	relatively siliceous
Comments:	weakly micaceous

Stone code:	SB4
Stone name:	Buff sandstone 4
Reference building:	25-29 Newmarket Street PRIMARY KE 963267 and 963266
Colour of exposed surfaces:	light grey to light greyish buff
Grain-size:	medium-sand-grade and coarse-sand-grade
Primary sedimentary structure:	most blocks are uniform; parallel bedding developed locally; rare cross-bedding; rare lamination
Distinctive features:	micaceous; scattered flakes of carbonaceous matter are usually present, and curved to sinuous leaf fragments up to 5 cm long may be present; can be gritty locally; brown iron nodules up to 2 cm across are developed locally; Liesegang bands can be developed locally.
Composition:	impure

Stone code:	SB5
Stone name:	Buff sandstone 5
Reference building:	123-127 High Street (WH Smith) PRIMARY_KE 961149
Colour of exposed surfaces:	light brownish buff
Grain-size:	medium-sand-grade to coarse-sand-grade; even grain-size
Primary sedimentary structure:	essentially uniform; rare, faint hints of bedding
Distinctive features:	strongly micaceous; rare fragments of carbonaceous matter up to 3 cm long; rare iron nodules up to 1 cm across; speckled character given by scattered, dark brown detrital grains up to 3 mm diameter
Composition:	impure

Stone code:	SB6
Stone name:	Buff sandstone 6
Reference building:	1 Mission Lane/9 Dundee Court (middle section of elevation facing Williamson Street) PRIMARY_KE 961110
Colour of exposed surfaces:	dull yellow
Grain-size:	fine-sand-grade to medium-sand-grade; even grain-size
Primary sedimentary structure:	mainly uniform; parallel bedding developed locally; cross bedding developed rarely
Distinctive features:	micaceous
Composition:	impure
Comments:	stone appears to have a high clay content; stugging conceals the primary sedimentary structure in many blocks; spalling extensively where face-bedded

Stone code:	SB7
Stone name:	Buff sandstone 7
Reference building:	dressings to tenement at 36-44 Melrose Place, Dundee Court PRIMARY_KE 961203 & 961204
Colour of exposed surfaces:	dull yellowish buff
Grain-size:	coarse-sand-grade to very-coarse-sand-grade; locally gritty
Primary sedimentary structure:	uniform, parallel bedded and cross-bedded
Distinctive features:	locally micaceous; gritty
Composition:	siliceous
Comments:	this stone found only as dressings

The photograph at right is centred on the door of the tenement building in which SB7 forms the dressings (dull yellow blocks)

Stone code:	SBM1
Stone name:	Modern buff sandstone 1
Reference building:	indents to Tattie Kirk, off Cow Wynd PRIMARY_KE 961108
Colour of exposed surfaces:	buff
Grain-size:	fine-sand-grade to medium-sand-grade; even grain-size
Primary sedimentary structure:	most blocks are uniform; faint bedding visible locally
Distinctive features:	rare flakes of carbonaceous matter up to 5 cm long
Composition:	impure
Comments:	weakly to moderately micaceous

The photograph at bottom shows part of Tattie Kirk, where SBM1 forms indents to the window dressings and replacement quoins.

Stone code:	SBM2
Stone name:	Modern buff sandstone 2
Reference building:	Fa’ Kirk (Old Parish Church); also known as Falkirk Old and St Modans Church, Manse Place; elevation facing Newmarket Street PRIMARY_KE 46333727
Colour of exposed surfaces:	dull greyish buff
Grain-size:	medium-sand-grade
Primary sedimentary structure:	most blocks are uniform; faint bedding visible locally
Distinctive features:	weakly gritty
Composition:	impure

The photograph at right shows where SBM2 has been used to build a modern addition to the Newmarket Street elevation of Fa’ Kirk.

Stone code:	SBM3
Stone name:	Modern buff sandstone 3
Reference building:	3 Vicar Street PRIMARY_KE 963224
Colour of exposed surfaces:	buff
Grain-size:	medium-sand-grade
Primary sedimentary structure:	uniform
Distinctive features:	flakes of carbonaceous matter, iron nodules and a gritty character are generally rare but common locally; Liesegang bands are developed locally; coloured spots up to 10 cm diameter are developed around small iron nodules
Composition:	impure

Stone code:	SBM4
Stone name:	Modern buff sandstone 4
Reference building:	ground and lower floors of The Steeple, High Street PRIMARY_KE 961318
Colour of exposed surfaces:	buff
Grain-size:	medium-sand-grade; even grain-size
Primary sedimentary structure:	uniform (weakly aligned flakes of carbonaceous matter reveal the bedding orientation in some blocks)
Distinctive features:	weakly micaceous; scarce flakes of carbonaceous matter are up to 2-3 cm long; nodules of hard brown iron up to 2 cm across are developed locally, with small iron-stained halos; rare fossil shell fragments are up to 8-9 cm long
Composition:	impure
Comment:	in 10 Newmarket Centre, (PRIMARY_KE 963303) this stone is fine-sand-grade

The ground and first floor levels of The Steeple are clad in SBM4.

Stone code:	SBM5
Stone name:	Modern buff sandstone 5
Reference building:	indents to Lloyds TSB, 137-139 High Street PRIMARY_KE 961164
Colour of exposed surfaces:	dark buff to buff
Grain-size:	coarse-sand-grade; even grain-size
Primary sedimentary structure:	essentially uniform; aligned flakes of carbonaceous matter and mica define the bedding orientation locally
Distinctive features:	micaceous; scattered flakes up to 1 cm long and circles (leafs) up to 8 cm long of carbonaceous matter are common
Composition:	impure

The photograph at right shows SBM5 indents to the right of the window.

Stone code:	SBM6
Stone name:	Modern buff sandstone 6
Reference building:	ground floor addition to 138-140 High Street PRIMARY_KE 961316
Colour of exposed surfaces:	buff
Grain-size:	generally medium-sand-grade to coarse-sand-grade; locally granule-grade
Primary sedimentary structure:	parallel bedding, cross-bedding, lamination and wispy lamination are all developed locally
Distinctive features:	gritty character and Liesegang bands are developed locally
Composition:	impure

The photograph at right shows the shop front addition to the Bank of Scotland building, which is made entirely of SBM6.

Stone code:	SO1
Stone name:	Orange sandstone 1
Reference building:	St Andrew's West Church, Upper Newmarket Street PRIMARY_KE 46333726
Colour of exposed surfaces:	orange to pink
Grain-size:	medium-sand-grade
Primary sedimentary structure:	regular, parallel lamination; rare blocks show cross-bedding
Distinctive features:	speckled character given by scattered grains of white feldspar; rare granulation seams; grey siliceous laminae
Composition:	siliceous
Comments:	very rare, hairline veins of calcite

Stone code:	SO2
Stone name:	Orange sandstone 2
Reference building:	41-43 Vicar Street PRIMARY_KE 963216 & 963217
Colour of exposed surfaces:	orange
Grain-size:	fine-sand-grade
Primary sedimentary structure:	parallel bedding, cross-bedding and parallel lamination
Distinctive features:	scattered shallow pits ~1 cm diameter, sometimes concentrated in bands
Composition:	siliceous

Stone code:	L
Stone name:	shelly limestone
Reference building:	165-169 High Street PRIMARY_KE 961200
Colour of exposed surfaces:	pale grey
Grain-size:	fine-sand-grade to medium-sand-grade
Primary sedimentary structure:	weak bedding defined locally by aligned shell fragments
Distinctive features:	abundant shell fragments up to 10 cm long
Composition:	shelly limestone

Stone code:	G1
Stone name:	Granite 1
Reference building:	plinth of South African War Memorial, Newmarket Street PRIMARY_KE 930773
Colour of exposed surfaces:	very pale orangeish grey
Grain-size:	coarse-crystalline (fine division)
Texture:	equigranular; weakly foliated
Distinctive features:	none
Composition:	muscovite-biotite granite

Stone code:	G2
Stone name:	Granite 2
Reference building:	base course of 137-139 High Street PRIMARY_KE 961164
Colour of exposed surfaces:	dark grey
Grain-size:	coarse crystalline (fine to medium division)
Texture:	largely equigranular but weakly inequigranular (feldspar-phyric) in places; foliated
Distinctive features:	micaceous; scattered black patches (mafic enclaves) up to 5 cm across
Composition:	biotite-rich granodiorite

Stone code:	G3
Stone name:	Granite 3
Reference building:	base course 134-136 High Street PRIMARY_KE 961315 & 961350
Colour of exposed surfaces:	greyish pink
Grain-size:	coarse-crystalline (medium to coarse division)
Texture:	inequigranular (weakly feldspar-phyric); massive
Distinctive features:	rare dark patches (mafic enclaves) are up to 3 cm across
Composition:	biotite granite

Stone code:	G4
Stone name:	Granite 4
Reference building:	columns in main door arch, 12-14 Newmarket Street PRIMARY_KE 963306
Colour of exposed surfaces:	brownish pink
Grain-size:	coarse-crystalline (medium division)
Texture:	equigranular; massive
Distinctive features:	none
Composition:	biotite granite