Approximately 30,000 tonnes of building stone, from five different localities, are present in the exterior of the building. This paper first describes the imported stone, then the local building stone. The formation, source and principal use of the exterior building stones are summarized in Table 1 and discussed below.

The building stone originally used to construct the rubble facing in the main walls, façade and higher sections of the towers in the Basilica was a rough, undressed, grey limestone from County Galway, Ireland. The stone is a light grey crinoidal packstone that contains abundant coral macrofossils (Fig. 3). Bishop Fleming also described using "black Galway marble ashlars" (Fitzgerald, 1997), although at present, none of this black limestone has been identified in the Basilica. The limestone is part of the Galway-Roscommon Shelf, a Viséan succession that consists almost entirely of limestones of shallow-water shelf facies extending from east County Clare and County Galway in the south, to counties Mayo and Roscommon in the north (Sevastopulo and Wyse Jackson, 2001).

During the early 19^th century limestone from quarries in the towns of Angliham (Fig. 4) and Menlough, located on the southeast shore of Lough Corrib in County Galway, was exported to localities throughout Britain and North America. The most valuable stone was black limestone from the Angliham quarry that was marketed under the name London Black, due to its great demand in the city of London. In addition to the black limestone, the quarries also produced vast quantities of grey limestone. The stone was transported by barge to the quay in Galway City, where it sold for five shillings and sixpence a foot (Feely, 2002). The first of numerous shipments of limestone from Galway arrived in St. John's by early 1841 and were transported to the building site by Bishop Fleming and the people of St. John's using between 70 and 80 wagons, which were donated by local farmers and shopkeepers.

Leinster granite from Dublin, Ireland was the principal material used in constructing the quoins, mouldings, lintels, cornices and window frames. This stone was also used to construct the statue pedestals, retaining walls and triple-span arch in the piazza. Several varieties of Leinster granite were used to construct the quoins, dressings, arch, and tower bases. The statue pedestals (Fig. 5) are a grey, medium- to coarse-grained, undeformed hornblende tonalite or quartz diorite. This stone is also present in the central archway. The tower bases (Fig. 6) and door frames are a white, medium- to coarse-grained, foliated muscovite-biotite granite that contains muscovite phenocrysts measuring up to 2 cm in diameter. The lintels, window frames, and cornices are a grey, medium-grained, equigranular muscovite-biotite granite that appears to be a finer-grained variety of the tower base and doorway muscovite-biotite granites.

The outer archways, which were added later in 1907, are a pink, massive, coarse-grained, K-feldspar porphyritic biotite granite containing biotite psammite xenoliths. Some of the quoins at the sides around the main entrance consist of a pink, K-feldspar porphyritic biotite granite that is similar to those used in the outer archways. These porphyritic granites are similar to Devonian K-feldspar porphyritic biotite granites found throughout the Appalachians and Caledonides (Dickson, pers. comm., 2003). The source(s) of this building stone are presently unknown.

The Leinster Granite Batholith is a composite two-mica peraluminous granite intrusion of more than 1500 km² and is the largest body of granite in Ireland and Britain. The batholith comprises five dome-like plutons that consist of quartz diorite to granodiorite, microcline-porphyritic and equigranular adamellite with coarse-grained varieties containing muscovite phenocrysts up to 70 mm (Stillman, 2001). Some of the granites used in the Basilica contain a pervasive foliation, the result of late Appalachian-Caledonian orogenic time of emplacement.

A vast quarry in Dalkey(Fig. 7), located approximately 14 km south of Dublin City centre, commenced operation in 1817 as a result of the need for stone to build the pier of Dun Laoghaire Harbour. The stone was transported from the quarry on lorries running on a narrow gauge tramway referred to locally as "The Metals". It is estimated that six million tons of stone were quarried and transported down the tramway. The quarry was abandoned in 1914 when the land was taken over by the Dun Laoghaire Borough Corporation and designated a public park. Although Bishop Fleming makes no reference to purchasing stone specifically from the Dalkey quarry, the years of operation, overall size of the quarry, type of stone quarried and location of the Dalkey quarry suggest that it is the most likely candidate for the source of the Leinster granite used in the Basilica.

In June 1840, Bishop Fleming left St. John's and sailed across the Atlantic to Ireland. He arrived in Cork on July 16 and for the next six weeks was engaged in a frantic round of activity in trying to procure building materials for the Basilica's construction. Fleming discovered that it was as cheap or cheaper to get stone from Ireland as in Newfoundland, since wages were lower and the ship owners were willing to transport the stone in the springtime at a low price so as to use it for ballast. He contracted with a master mason in Dublin for cut granite to the amount of £1,200 sterling, and hired a ship to transport this stone to Newfoundland for £270 sterling. The stone was unloaded at "the Bishop's Wharf " in St. John's where the townspeople brought their carts to the wharf and conveyed the stone to the Basilica grounds. Each day a different society or occupation would gather and cart the stone required for that day's work to the building site (Darcy, 2003).

Sandstone used in the foundation of the building was quarried from Signal Hill, a prominent landmark on the east side of the city of St. John's, situated approximately 1 km from the Basilica. Signal Hill Group sandstone was also used in originally constructing the parts of the ambulatory walls. Quarries are known to have operated on Signal Hill (Fig. 8) since at least 1690 and in the past supplied material for foundations, bridge abutments, retaining walls and for old fortifications built to defend St. John's against French and Dutch invasions.

The stone used in the foundations is part of the Lower Precambrian Quidi Vidi Formation of the Signal Hill Group. King (1990) described the stone as a medium- to thick-bedded, red, arkosic sandstone having thin to medium interbeds of siltstone, mudstone, intraformational breccia, red conglomerate and green sandstone. Finely disseminated hematite surrounds the dominantly felsic volcanic clasts and gives the rock its red colour.

At least 2000 tonnes of Signal Hill Group sandstone were used in constructing the foundations of the Basilica. In 1839, the Lieutenant Colonel of the Government engineering department offered Bishop Fleming the loose red sandstone that was left on Signal Hill from construction of a military road. Fleming relayed the news to his congregation and asked for their help in transporting the stone. Three days later 6000 people awaited instructions at the foot of Signal Hill and divided themselves into different factions consisting of residents of the same street, different societies and occupations. A rivalry so great arose, as each group tried to prove that it could carry the most, that by nightfall they had moved 1,200 tonnes of the rock, some individually weighing upwards of 10 tonnes, by hand on sledges to the Basilica site (Martin, 1983).

The stone used in the reconstruction of the exterior walls of the Basilica is thickly bedded, massive grey sandstone (Fig. 9) of the Gibbett Hill Formation, the stratigraphically lowest unit of the Signal Hill Group. The rock is typically medium- to coarse-grained and lithofeldspathic to arkosic in composition. The sandstone shows parallel laminations, grading and mud cracks, sandstone dykes, and trough cross-stratification (King, 1990). The major quarry supplying Gibbett Hill sandstone for the Basilica operated intermittently from the 1870s to 1950s and was located at the Southside Hills of St. John's. In the late 1980s this quarry was temporarily reactivated to supply the small quantities of stone required for the Basilica's restoration. The quarry site is now a storage area for the Canadian Coast Guard.

The Signal Hill Group is interpreted to have been deposited subaerially during alluvial plain conditions that developed across the Avalon Zone in easternmost Newfoundland during the Neoproterozoic in response to a major uplift related to the Avalonian Orogeny (King, 1990).

A large quantity of sandstone from Kellys Island was utilized in constructing the foundations of the Basilica and in the lower sections of the main and rear ambulatory walls. Kellys Island is situated in Conception Bay, approximately 25 km west of St. John's.

The Tremadoc Kellys Island Formation is the basal unit of the Bell Island Group, a 1200 m thick succession of Ordovician, marine, platformal, sedimentary rocks. The Kellys Island Formation consists of white, massive sandstone interbedded with fissile, dark, silty shale and intercalated, micaceous, sandy siltsone, silty shale and thin- to medium-bedded, rippled sandstone. The stone used in the Basilica was quarried from the top of the formation in a massive white sandstone unit at least 8 m thick. This rock contains wavy, flaser, and lenticular beds along with trace fossils, desiccation cracks, runzel marks, and current formed ripples. Some of the sandstone units are pale green, a result of the presence of chamosite and chlorite (Ranger et al., 1984).

Several thousand tonnes of sandstone were quarried from Kellys Island between 1838 and 1841. The work was supervised by Bishop Fleming himself, who lived on the island five days a week, several months of the year, for several years. The stone was extracted from the quarry during autumn and shipped to St. John's the following spring by "every Catholic owner of a schooner, and even some Protestants, who volunteered to send their vessels gratuitously to Kelly's Island" (Fleming, 1841), a distance for some over water of 325 km. This method of transportation was sporadic and precarious however, as the size, type and availability of boats accessible in Newfoundland prevented the shipping of a sufficient quantity of stone from Kellys Island to keep up with the pace of construction. As a result the quarry was abandoned in late 1841 or early 1842.

In an effort to procure only local stone in building the Basilica, Bishop Fleming established two quarries near the periphery of St. John's at Long Pond and Mundy Pond. The stone quarried from these locations is red and green tuffaceous siltstone and sandstone of the Mistaken Point Formation, the uppermost unit of the Neoproterozoic Conception Group (Williams and King, 1979).

Near St. John's the Mistaken Point Formation consists of a 400 m thick succession of mainly green and reddish purple argillaceous siltstone and very fine-grained sandstone. The rocks generally appear to be massive; however, medium to thick beds, parallel laminations and grading are recognizable. The red to green colour changes are diagenetic and may be independent of bedding (King, 1990). The Mistaken Point Formation is perhaps best known for its Ediacarian fossils present south of St. John's at Mistaken Point. The Mistaken Point Formation is interpreted to represent a Neoproterozoic period of explosive volcanic activity associated with submarine turbiditic sedimentation in the peri-Gondwanan Avalon Zone.

Approximately 1,000 tonnes of building stone were extracted from the Long Pond and Mundy Pond quarries and transported by sledge to the building site over a period of four days in February 1842 (Darcy, 2003). At this time it was evident that these quarries could not supply the quantity of stone needed for the Basilica and therefore they ceased operation. An examination of the Basilica by the author located only a small number of sandstone blocks in the walls (Fig. 10) that could be positively identified as belonging to the Mistaken Point Formation. Efforts to locate the quarries today have failed because these areas of former bedrock are now housing or commercial estates.

Stone for the Basilica was also supplied from the Outer Cove area, located 8 km north of St. John's, by the residents of the communities of Torbay, Outer Cove, Middle Cove and Logy Bay. The stone was transported to St. John's in 1845 by approximately 150 horses, each of which carried two loads of stone (Lahey, 1980). This rock could possibly be from the Conception Group, St. John's Group or Signal Hill Group (King, 1990). The amount of stone quarried and the location of a possible quarry is unknown. The stone, however, might also have been obtained from the cliffs at Outer Cove (St. John's Group).

Carrara marble is the most abundant building stone used in the interior of the Basilica. The colours and characteristics of the marble vary throughout the church, however, all are referred to as Carrara marble. A white marble with variable grey banding is the principal material used in the high altar and seven side altars, balusters and steps, baptistery, pulpit, and eight memorial tablets to the former Bishops and Archbishops of St. John's. This stone was also used to construct the caskets for the one Archbishop and four Bishops who are buried in the crypt of the Basilica. The purest white Carrara marble was used to carve the numerous statues (Fig. 11) located throughout church, and consists of a fully recrystallized limestone that is world-renowned and marketed as "statuario" marble. This marble typically has a granoblastic saccharoidal texture due to metamorphic recrystallization of limestone. A piece of this flawless, pure bright-white Carrara marble was used to carve the most revered and valuable piece of statuary in the Basilica; prominent Irish sculptor John Hogan's statue of "The Dead Christ". It is the final of three similar statues created by Hogan in the early 19th century and the only one presently located outside Ireland. Carrara marbles originated in a Late Triassic-Jurassic carbonate continental shelf in the Tuscanian Apennines, which was subsequently deformed in the Tertiary-Pliocene during the Apennine Orogeny (Lindquist, 1999). This orogenic event resulted in the low-grade metamorphism responsible for the recrystallization of the limestone.

Marble deposits in the Carrara region of northern Tuscany in Italy have been quarried for the past two millennia. The stone was initially extracted at the height of the Roman Empire; during the Imperial age (500 B.C. to 500 A.D.) Carrara marble became the most requested building stone for public buildings in Italy. Production has steadily increased to the present day as Carrara marble is exported throughout the world for use in buildings and sculptures. An estimated 300 quarries are currently in operation and produce approximately a million tonnes of marble per year (Leivick and Leitch, 1999).

The top rail of the high altar is comprised of yellow Verona marble (actually a limestone) and was ordered from Italy in 1914 by Archbishop Howley. The stone is light yellow to creamy-brown, nodular limestone (Fig. 12). The origin of the nodular texture is thought to be as a result of local dissolution and reprecipitation of CaCO₃ in the sediment, with later compaction and pressure dissolution enhancing the nodularity (Jenkyns, 1974). This pressure solution is also responsible for the numerous styolites throughout the stone. They generally form an irregular network of suture-like contacts up to several mm in thickness and are composed of an insoluble brown clay or iron oxide material.

The province of Verona is one of Italy's most important marble producing areas and there have been working quarries and workshops present since Roman times. There has therefore been a community of stonemasons in Verona for over 2000 years who have, at least until the arrival of industrial processes, been quarrying the limestone using techniques almost unchanged through the Middle Ages right up to the mid-20^th century.

Egyptian travertine is often referred to as Oriental alabaster since in ancient times the early examples came from the Far East. This rock is the so-called "Egyptian alabaster" of archaeologists and historians, whose name was derived from the town of Alabastron, in Egypt, where the stone was quarried; this rock is also referred to as calcitic or calcareous alabaster. This is the origin of the petrologically incorrect name of alabaster, which actually refers to a fine-grained variety of gypsum.

The travertine in the Basilica of St. John the Baptist was used to construct two side altars located in the transepts, east and west of the high alter. The stone consists of alternating concentric spherical bands of white to cream, fine-grained, and light brown, medium-grained calcite, with occasional coarse-grained amber to brown calcite (Fig. 13). The spheres measure up to 30 cm in diameter with individual calcite bands varying in width from several millimetres to 2 cm. Travertine forms by rapid chemical precipitation of calcium carbonate from solution in surface and groundwaters or by the evaporation around the mouth or in the conduit of a spring, primarily a hot spring. It also occurs along the floors and walls of limestone caverns, where it forms stalagmite and stalactite deposits, respectively.

Quarried from the late Predynastic period (5,500 - 3,100 B.C.) through the Roman period until 3^rd or 4^th century A.D., the ancient Egyptian travertine quarries in Middle Egypt on the East Bank of the Nile were rediscovered in the 19^th century by Muhammad Ali, Pasha of Egypt (1805-1848). In 1840, Ali Pasha presented portions of the travertine to Pope Gregory XVI, who used them to decorate the high altar of the Basilica of St. Paul Outside the Walls in Rome. A small quantity of this stone remained in Rome and, of this, two portions were offered by the Pope to Bishop Mullock, who subsequently brought the stone to St. John's in 1856 to complete the interior of the Basilica (Graham, 1984).